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Sample records for angle-resolved photoemission spectroscopy

  1. Integrated experimental setup for angle resolved photoemission...

    Office of Scientific and Technical Information (OSTI)

    Integrated experimental setup for angle resolved photoemission spectroscopy of transuranic materials Citation Details In-Document Search Title: Integrated experimental setup for...

  2. Angle-resolved photoemission spectroscopy study of PrFeAsO0.7: Comparison

    Office of Scientific and Technical Information (OSTI)

    with LaFePO (Journal Article) | SciTech Connect Angle-resolved photoemission spectroscopy study of PrFeAsO0.7: Comparison with LaFePO Citation Details In-Document Search Title: Angle-resolved photoemission spectroscopy study of PrFeAsO0.7: Comparison with LaFePO Authors: Nishi, I. ; Ishikado, M. ; Ideta, S. ; Malaeb, W. ; Yoshida, T. ; Fujimori, A. ; Kotani, Y. ; Kubota, M. ; Ono, K. ; Yi, M. ; Lu, D. H. ; Moore, R. ; Shen, Z.-X. ; Iyo, A. ; Kihou, K. ; Kito, H. ; Eisaki, H. ; Shamoto, S. ;

  3. A tunable low-energy photon source for high-resolution angle-resolved photoemission spectroscopy

    SciTech Connect (OSTI)

    Harter, John W.; Monkman, Eric J.; Shai, Daniel E.; Nie Yuefeng; Uchida, Masaki; Burganov, Bulat; Chatterjee, Shouvik; King, Philip D. C.; Shen, Kyle M.

    2012-11-15

    We describe a tunable low-energy photon source consisting of a laser-driven xenon plasma lamp coupled to a Czerny-Turner monochromator. The combined tunability, brightness, and narrow spectral bandwidth make this light source useful in laboratory-based high-resolution photoemission spectroscopy experiments. The source supplies photons with energies up to {approx}7 eV, delivering under typical conditions >10{sup 12} ph/s within a 10 meV spectral bandwidth, which is comparable to helium plasma lamps and many synchrotron beamlines. We first describe the lamp and monochromator system and then characterize its output, with attention to those parameters which are of interest for photoemission experiments. Finally, we present angle-resolved photoemission spectroscopy data using the light source and compare its performance to a conventional helium plasma lamp.

  4. Substrate interactions with suspended and supported monolayer MoS2: Angle-resolved photoemission spectroscopy

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Jin, Wencan; Yeh, Po -Chun; Zaki, Nader; Zhang, Datong; Liou, Jonathan T.; Dadap, Jerry I.; Barinov, Alexey; Yablonskikh, Mikhail; Sadowski, Jerzy T.; Sutter, Peter; et al

    2015-03-17

    We report the directly measured electronic structure of exfoliated monolayer molybdenum disulfide (MoS₂) using micrometer-scale angle-resolved photoemission spectroscopy. Measurements of both suspended and supported monolayer MoS₂ elucidate the effects of interaction with a substrate. Thus, a suggested relaxation of the in-plane lattice constant is found for both suspended and supported monolayer MoS₂ crystals. For suspended MoS₂, a careful investigation of the measured uppermost valence band gives an effective mass at Γ¯ and Κ¯ of 2.00m₀ and 0.43m₀, respectively. We also measure an increase in the band linewidth from the midpoint of Γ¯Κ¯ to the vicinity of Κ¯ and briefly discussmore » its possible origin.« less

  5. High-harmonic XUV source for time- and angle-resolved photoemission

    Office of Scientific and Technical Information (OSTI)

    spectroscopy (Conference) | SciTech Connect Conference: High-harmonic XUV source for time- and angle-resolved photoemission spectroscopy Citation Details In-Document Search Title: High-harmonic XUV source for time- and angle-resolved photoemission spectroscopy We present a laser-based apparatus for visible pump/XUV probe time- and angle-resolved photoemission spectroscopy (TRARPES) utilizing high-harmonic generation from a noble gas. Femtosecond temporal resolution for each selected harmonic

  6. High-harmonic XUV source for time- and angle-resolved photoemission...

    Office of Scientific and Technical Information (OSTI)

    High-harmonic XUV source for time- and angle-resolved photoemission spectroscopy Citation Details In-Document Search Title: High-harmonic XUV source for time- and angle-resolved...

  7. Electronic structure of Ce?RhIn?: A two-dimensional heavy-fermion system studied by angle-resolved photoemission spectroscopy

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Jiang, Rui; Petrovic, C.; Mou, Daixing; Liu, Chang; Zhao, Xin; Yao, Yongxin; Ryu, Hyejin; Ho, Kai -Ming; Kaminski, Adam

    2015-04-01

    We use angle-resolved photoemission spectroscopy (ARPES) to study the 2D heavy fermion superconductor, Ce?RhIn?. The Fermi surface is rather complicated and consists of several hole and electron pockets with one of the sheets displaying strong nesting properties with a q-vector of (0.32, 0.32) ?/a. We do not observe kz dispersion of the Fermi sheets, which is consistent with the expected 2D character of the electronic structure. Comparison of the ARPES data to band structure calculations suggests that a localized picture of the f-electrons works best. While there is some agreement in the overall band dispersion and location of the Fermimoresheets, the model does not reproduce all observed bands and is not completely accurate for those it does. Our data paves the way for improving the band structure calculations and the general understanding of the transport and thermodynamical properties of this material.less

  8. Electronic structure of Ce2RhIn8: A two-dimensional heavy-fermion system studied by angle-resolved photoemission spectroscopy

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Jiang, Rui; Mou, Daixing; Liu, Chang; Zhao, Xin; Yao, Yongxin; Ryu, Hyejin; Petrovic, C.; Ho, Kai -Ming; Kaminski, Adam

    2015-04-01

    We use angle-resolved photoemission spectroscopy (ARPES) to study the 2D heavy fermion superconductor, Ce₂RhIn₈. The Fermi surface is rather complicated and consists of several hole and electron pockets with one of the sheets displaying strong nesting properties with a q-vector of (0.32, 0.32) π/a. We do not observe kz dispersion of the Fermi sheets, which is consistent with the expected 2D character of the electronic structure. Comparison of the ARPES data to band structure calculations suggests that a localized picture of the f-electrons works best. While there is some agreement in the overall band dispersion and location of the Fermimore » sheets, the model does not reproduce all observed bands and is not completely accurate for those it does. As a result, our data paves the way for improving the band structure calculations and the general understanding of the transport and thermodynamical properties of this material.« less

  9. Angle-resolved environmental X-ray photoelectron spectroscopy: A new laboratory setup for photoemission studies at pressures up to 0.4 Torr

    SciTech Connect (OSTI)

    Mangolini, F.; Wabiszewski, G. E.; Egberts, P.; Ahlund, J.; Backlund, K.; Karlsson, P. G.; Adiga, V. P.; Streller, F.; Wannberg, B.; Carpick, R. W.

    2012-09-15

    The paper presents the development and demonstrates the capabilities of a new laboratory-based environmental X-ray photoelectron spectroscopy system incorporating an electrostatic lens and able to acquire spectra up to 0.4 Torr. The incorporation of a two-dimensional detector provides imaging capabilities and allows the acquisition of angle-resolved data in parallel mode over an angular range of 14 Degree-Sign without tilting the sample. The sensitivity and energy resolution of the spectrometer have been investigated by analyzing a standard Ag foil both under high vacuum (10{sup -8} Torr) conditions and at elevated pressures of N{sub 2} (0.4 Torr). The possibility of acquiring angle-resolved data at different pressures has been demonstrated by analyzing a silicon/silicon dioxide (Si/SiO{sub 2}) sample. The collected angle-resolved spectra could be effectively used for the determination of the thickness of the native silicon oxide layer.

  10. Doping Dependence of the $(\\pi,\\pi)$ Shadow Band in La-Based Cuprates Studied by Angle-Resolved Photoemission Spectroscopy

    SciTech Connect (OSTI)

    Shen, Z. X.

    2011-08-15

    The ({pi},{pi}) shadow band (SB) in La-based cuprate family (La214) was studied by angle-resolved photoemission spectroscopy (ARPES) over a wide doping range from x = 0.01 to x = 0.25. Unlike the well-studied case of the Bi-based cuprate family, an overall strong, monotonic doping dependence of the SB intensity at the Fermi level (E{sub F}) was observed. In contrast to a previous report for the presence of the SB only close to x = 1/8, we found it exists in a wide doping range, associated with a doping-independent ({pi},{pi}) wave vector but strongly doping-dependent intensity: It is the strongest at x {approx} 0.03 and systematically diminishes as the doping increases until it becomes negligible in the overdoped regime. This SB with the observed doping dependence of intensity can in principle be caused by the antiferromagnetic fluctuations or a particular form of low-temperature orthorhombic lattice distortion known to persist up to x {approx} 0.21 in the system, with both being weakened with increasing doping. However, a detailed binding energy dependent analysis of the SB at x = 0.07 does not appear to support the former interpretation, leaving the latter as a more plausible candidate, despite a challenge in quantitatively linking the doping dependences of the SB intensity and the magnitude of the lattice distortion. Our finding highlights the necessity of a careful and global consideration of the inherent structural complications for correctly understanding the cuprate Fermiology and its microscopic implication.

  11. Angle Resolved Photoemission Spectroscopy Studies of the Mott Insulator to Superconductor Evolution in Ca2-xNaxCuO2Cl2

    SciTech Connect (OSTI)

    Shen, Kyle Michael; ,

    2005-09-02

    It is widely believed that many of the exotic physical properties of the high-T{sub c} cuprate superconductors arise from the proximity of these materials to the strongly correlated, antiferromagnetic Mott insulating state. Therefore, one of the fundamental questions in the field of high-temperature superconductivity is to understand the insulator-to-superconductor transition and precisely how the electronic structure of Mott insulator evolves as the first holes are doped into the system. This dissertation presents high-resolution, doping dependent angle-resolved photoemission (ARPES) studies of the cuprate superconductor Ca{sub 2-x}Na{sub x}CuO{sub 2}Cl{sub 2}, spanning from the undoped parent Mott insulator to a high-temperature superconductor with a T{sub c} of 22 K. A phenomenological model is proposed to explain how the spectral lineshape, the quasiparticle band dispersion, and the chemical potential all progress with doping in a logical and self-consistent framework. This model is based on Franck-Condon broadening observed in polaronic systems where strong electron-boson interactions cause the quasiparticle residue, Z, to be vanishingly small. Comparisons of the low-lying states to different electronic states in the valence band strongly suggest that the coupling of the photohole to the lattice (i.e. lattice polaron formation) is the dominant broadening mechanism for the lower Hubbard band states. Combining this polaronic framework with high-resolution ARPES measurements finally provides a resolution to the long-standing controversy over the behavior of the chemical potential in the high-T{sub c} cuprates. This scenario arises from replacing the conventional Fermi liquid quasiparticle interpretation of the features in the Mott insulator by a Franck-Condon model, allowing the reassignment of the position of the quasiparticle pole. As a function of hole doping, the chemical potential shifts smoothly into the valence band while spectral weight is transferred from incoherent weight at high energies to a coherent quasiparticle peak near E{sub F}. The combined shift in the chemical potential and Fermi wavevector, k{sub F}, closely corresponds to a rigid band shift into the faint excitation branch defined by the low-energy quasiparticles. In addition, the detailed doping evolution of the low-energy excitations has been studied throughout k-space. A large, hole-like contour emerges with doping, although well-defined quasiparticle peaks are only observed along a small arc around the (0, 0)-({pi},{pi}) nodal line. Near the ({pi}, 0) antinodes, faint parallel segments are found with a nesting wavevector and energy dependence very similar to the 4a{sub 0} x 4a{sub 0} checkerboard pattern observed by scanning tunneling microscopy. However, these measurements reveal a striking dichotomy between the real and momentum-space probes, where antinodal charge ordering is emphasized in the tunnelling measurements, while ARPES is most sensitive to excitations near the d-wave nodal line. These results emphasize the importance of momentum anisotropy in determining the complex electronic properties of the cuprates and places strong constraints on theoretical models of the charge ordered state.

  12. Quasiparticle dynamics across the full Brillouin zone of Bi2Sr2CaCu2O8+δ traced with ultrafast time and angle-resolved photoemission spectroscopy

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Dakovski, Georgi L.; Durakiewicz, Tomasz; Zhu, Jian-Xin; Riseborough, Peter S.; Gu, Genda; Gilbertson, Steve M.; Taylor, Antoinette; Rodriguez, George

    2015-10-12

    A hallmark in the cuprate family of high-temperature superconductors is the nodal-antinodal dichotomy. In this regard, angle-resolved photoemission spectroscopy (ARPES) has proven especially powerful, providing band structure information directly in energy-momentum space. Time-resolved ARPES (trARPES) holds great promise of adding ultrafast temporal information, in an attempt to identify different interaction channels in the time domain. Previous studies of the cuprates using trARPES were handicapped by the low probing energy which significantly limits the accessible momentum space. Using 20.15eV, 12 fs pulses we show for the first time the evolution of quasiparticles in the antinodal region of Bi2Sr2CaCu2O8+δ and demonstrate thatmore »nonmonotonic relaxation dynamics dominates above a certain fluence threshold. The dynamics is heavily influenced by transient modification of the electron-phonon interaction and phase space restrictions, in severe contrast to the monotonic relaxation in the nodal and off-nodal regions.« less

  13. Quasiparticle dynamics across the full Brillouin zone of Bi2Sr2CaCu2O8+δ traced with ultrafast time and angle-resolved photoemission spectroscopy

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Dakovski, Georgi L.; Durakiewicz, Tomasz; Zhu, Jian-Xin; Riseborough, Peter S.; Gu, Genda; Gilbertson, Steve M.; Taylor, Antoinette; Rodriguez, George

    2015-10-12

    A hallmark in the cuprate family of high-temperature superconductors is the nodal-antinodal dichotomy. In this regard, angle-resolved photoemission spectroscopy (ARPES) has proven especially powerful, providing band structure information directly in energy-momentum space. Time-resolved ARPES (trARPES) holds great promise of adding ultrafast temporal information, in an attempt to identify different interaction channels in the time domain. Previous studies of the cuprates using trARPES were handicapped by the low probing energy which significantly limits the accessible momentum space. Using 20.15eV, 12 fs pulses we show for the first time the evolution of quasiparticles in the antinodal region of Bi2Sr2CaCu2O8+δ and demonstrate thatmore » nonmonotonic relaxation dynamics dominates above a certain fluence threshold. The dynamics is heavily influenced by transient modification of the electron-phonon interaction and phase space restrictions, in severe contrast to the monotonic relaxation in the nodal and off-nodal regions.« less

  14. Design of a High Resolution and High Flux Beam line for VUV Angle-Resolved Photoemission at UVSOR-II

    SciTech Connect (OSTI)

    Kimura, Shin-ichi; Ito, Takahiro; Nakamura, Eiken; Hosaka, Masahito; Katoh, Masahiro

    2007-01-19

    A high-energy-resolution angle-resolved photoemission beamline in the vacuum-ultraviolet (VUV) region has been designed for a 750 MeV synchrotron light source UVSOR-II. The beamline equips an APPLE-II-type undulator with the horizontally/vertically linear and right/left circular polarizations, a modified Wadsworth-type monochromator and a high-resolution photoelectron analyzer. The monochromator covers the photon energy range of 6 - 40 eV. The energy resolution (hv/{delta}hv) and the photon flux on samples are expected to be 2 x 104 and 1012 photons/sec at 10 eV, 4 x 104 and 5 x 1011 photons/sec at 20 eV, and 6 x 104 and 1011 photons/sec at 40 eV, respectively. The beamline provides the high-resolution angle-resolved photoemission spectroscopy less than 1 meV in the whole VUV energy range.

  15. High-harmonic XUV source for time- and angle-resolved photoemission...

    Office of Scientific and Technical Information (OSTI)

    Sponsoring Org: DOE Country of Publication: United States Language: English Subject: 36; HARMONICS; MONOCHROMATORS; PHOTOEMISSION; PROBES; RESOLUTION; SPECTRA; SPECTROSCOPY Word ...

  16. SAMRAI: A novel variably polarized angle-resolved photoemission beamline in the VUV region at UVSOR-II

    SciTech Connect (OSTI)

    Kimura, Shin-Ichi; Ito, Takahiro; Hosaka, Masahito; Katoh, Masahiro; Sakai, Masahiro; Nakamura, Eiken; Kondo, Naonori; Horigome, Toshio; Hayashi, Kenji; Goto, Tomohiro; Ejima, Takeo; Soda, Kazuo

    2010-05-15

    A novel variably polarized angle-resolved photoemission spectroscopy beamline in the vacuum-ultraviolet (VUV) region has been installed at the UVSOR-II 750 MeV synchrotron light source. The beamline is equipped with a 3 m long APPLE-II type undulator with horizontally/vertically linear and right/left circular polarizations, a 10 m Wadsworth type monochromator covering a photon energy range of 6-43 eV, and a 200 mm radius hemispherical photoelectron analyzer with an electron lens of a {+-}18 deg. acceptance angle. Due to the low emittance of the UVSOR-II storage ring, the light source is regarded as an entrance slit, and the undulator light is directly led to a grating by two plane mirrors in the monochromator while maintaining a balance between high-energy resolution and high photon flux. The energy resolving power (h{nu}/{Delta}h{nu}) and photon flux of the monochromator are typically 1x10{sup 4} and 10{sup 12} photons/s, respectively, with a 100 {mu}m exit slit. The beamline is used for angle-resolved photoemission spectroscopy with an energy resolution of a few meV covering the UV-to-VUV energy range.

  17. A New Spin on Photoemission Spectroscopy

    SciTech Connect (OSTI)

    Advanced Light Source; Jozwiak, Chris

    2008-12-18

    The electronic spin degree of freedom is of general fundamental importance to all matter. Understanding its complex roles and behavior in the solid state, particularly in highly correlated and magnetic materials, has grown increasingly desirable as technology demands advanced devices and materials based on ever stricter comprehension and control of the electron spin. However, direct and efficient spin dependent probes of electronic structure are currently lacking. Angle Resolved Photoemission Spectroscopy (ARPES) has become one of the most successful experimental tools for elucidating solid state electronic structures, bolstered bycontinual breakthroughs in efficient instrumentation. In contrast, spin-resolved photoemission spectroscopy has lagged behind due to a lack of similar instrumental advances. The power of photoemission spectroscopy and the pertinence of electronic spin in the current research climate combine to make breakthroughs in Spin and Angle Resolved Photoemission Spectroscopy (SARPES) a high priority . This thesis details the development of a unique instrument for efficient SARPES and represents a radical departure from conventional methods. A custom designed spin polarimeter based on low energy exchange scattering is developed, with projected efficiency gains of two orders of magnitude over current state-of-the-art polarimeters. For energy analysis, the popular hemispherical analyzer is eschewed for a custom Time-of-Flight (TOF) analyzer offering an additional order of magnitude gain in efficiency. The combined instrument signifies the breakthrough needed to perform the high resolution SARPES experiments necessary for untangling the complex spin-dependent electronic structures central to today?s condensed matter physics.

  18. CORPES 11: International Workshop on Strong Correlations and Angle-Resolved

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Photoemission Spectroscopy CORPES 11: International Workshop on Strong Correlations and Angle-Resolved Photoemission Spectroscopy July 18-22, 2011 Lawrence Berkeley National Laboratory, California More information Attendees participated in a poster session Thursday on the ALS patio, engaging in conversations over lunch and at the posters. An international workshop entitled "Strong Correlations and Angle-Resolved Photoemission Spectroscopy", or CORPES11 , was held at Berkeley Lab

  19. Aspects of Electron-Phonon Self-Energy Revealed From Angle-Resolved

    Office of Scientific and Technical Information (OSTI)

    Photoemission Spectroscopy (Journal Article) | SciTech Connect Aspects of Electron-Phonon Self-Energy Revealed From Angle-Resolved Photoemission Spectroscopy Citation Details In-Document Search Title: Aspects of Electron-Phonon Self-Energy Revealed From Angle-Resolved Photoemission Spectroscopy No abstract prepared. Authors: Lee, W.S. ; /Stanford U., Appl. Phys. Dept. /SLAC, SSRL ; Johnston, S. ; Devereaux, T.P. ; /Waterloo U. ; Shen, Z.X. ; /Stanford U., Appl. Phys. Dept. /SLAC, SSRL

  20. Aspects of Electron-Phonon Self-Energy Revealed From Angle-Resolved...

    Office of Scientific and Technical Information (OSTI)

    Aspects of Electron-Phonon Self-Energy Revealed From Angle-Resolved Photoemission Spectroscopy Citation Details In-Document Search Title: Aspects of Electron-Phonon Self-Energy...

  1. Photoemission Spectroscopy at SRI2013

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Photoemission Spectroscopy at SRI2013 Workshop on Photoemission Spectroscopy: The Upcoming Decades Organizers: Alexei Fedorov (ALS) and Peter Johnson (BNL) Tuesday, June 18, 2013 * Location TBD 9:00 a.m.-17:00 p.m. Workshop to take place during SRI 2013 in Washington, D.C., June 19-21, 2013

  2. Angle-resolved photoemission spectroscopy study of PrFeAsO0.7...

    Office of Scientific and Technical Information (OSTI)

    Authors: Nishi, I. ; Ishikado, M. ; Ideta, S. ; Malaeb, W. ; Yoshida, T. ; Fujimori, A. ; Kotani, Y. ; Kubota, M. ; Ono, K. ; Yi, M. ; Lu, D. H. ; Moore, R. ; Shen, Z.-X. ; Iyo, A. ...

  3. Laser Focus World highlights Kaminski's home-grown ARPES spectroscopy...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Laser Focus World highlights Kaminski's home-grown ARPES spectroscopy system Laser Focus World senior editor Gail Overton wrote a story on angled-resolved photo-emission...

  4. Angle-Resolved Photoemission Studies of Quantum Materials (Journal...

    Office of Scientific and Technical Information (OSTI)

    Have feedback or suggestions for a way to improve these results? Save Share this Record Citation Formats MLA APA Chicago Bibtex Export Metadata Endnote Excel CSV XML Save to My ...

  5. A high-efficiency spin-resolved photoemission spectrometer combining time-of-flight spectroscopy with exchange-scattering polarimetry

    SciTech Connect (OSTI)

    Jozwiak, Chris M.; Graff, Jeff; Lebedev, Gennadi; Andresen, Nord; Schmid, Andreas; Fedorov, Alexei; El Gabaly, Farid; Wan, Weishi; Lanzara, Alessandra; Hussain, Zahid

    2010-04-13

    We describe a spin-resolved electron spectrometer capable of uniquely efficient and high energy resolution measurements. Spin analysis is obtained through polarimetry based on low-energy exchange scattering from a ferromagnetic thin-film target. This approach can achieve a similar analyzing power (Sherman function) as state-of-the-art Mott scattering polarimeters, but with as much as 100 times improved efficiency due to increased reflectivity. Performance is further enhanced by integrating the polarimeter into a time-of-flight (TOF) based energy analysis scheme with a precise and flexible electrostatic lens system. The parallel acquisition of a range of electron kinetic energies afforded by the TOF approach results in an order of magnitude (or more) increase in efficiency compared to hemispherical analyzers. The lens system additionally features a 90 degrees bandpass filter, which by removing unwanted parts of the photoelectron distribution allows the TOF technique to be performed at low electron drift energy and high energy resolution within a wide range of experimental parameters. The spectrometer is ideally suited for high-resolution spin- and angle-resolved photoemission spectroscopy (spin-ARPES), and initial results are shown. The TOF approach makes the spectrometer especially ideal for time-resolved spin-ARPES experiments.

  6. Xe and Ar nanobubbles in Al studied by photoemission spectroscopy (Journal

    Office of Scientific and Technical Information (OSTI)

    Article) | SciTech Connect Xe and Ar nanobubbles in Al studied by photoemission spectroscopy Citation Details In-Document Search Title: Xe and Ar nanobubbles in Al studied by photoemission spectroscopy We have studied xenon and argon bubbles formed in the subsurface region of Al(111) by x-ray photoelectron spectroscopy. As a consequence of the nanometer size of the bubbles, the photohole formed by Xe 3d or Ar 2p photoemission is screened by the Al conduction electrons, which substantially

  7. TOF Electron Energy Analyzer for Spin and Angular Resolved Photoemission Spectroscopy

    SciTech Connect (OSTI)

    Lebedev, Gennadi; Jozwiak, Chris; Andresen, Nord; Lanzara, Alessandra; Hussain, Zahid

    2008-07-09

    Current pulsed laser and synchrotron x-ray sources provide new opportunities for Time-Of- Flight (TOF) based photoemission spectroscopy to increase photoelectron energy resolution and efficiency compared to current standard techniques. The principals of photoelectron timing front formation, temporal aberration minimization, and optimization of electron beam transmission are presented. We have developed these concepts into a high resolution Electron Optical Scheme (EOS) of a TOF Electron Energy Analyzer (TOF-EEA) for photoemission spectroscopy. The EOS of the analyzer includes an electrostatic objective lens, three columns of transport lenses and a 90 degree energy band pass filter (BPF). The analyzer has two modes of operation: Spectrometer Mode (SM) with straight passage of electrons through the EOS undeflected by the BPF, allowing the entire spectrum to be measured, and Monochromator Mode (MM) in which the BPF defines a certain energy window inside the scope of the electron energy spectrum.

  8. Photoemission spectroscopy study of the lanthanum lutetium oxide/silicon interface

    SciTech Connect (OSTI)

    Nichau, A.; Schnee, M.; Schubert, J.; Bernardy, P.; Hollaender, B.; Buca, D.; Mantl, S.; Besmehn, A.; Breuer, U.; Rubio-Zuazo, J.; Castro, G. R.; Muecklich, A.; Borany, J. von

    2013-04-21

    Rare earth oxides are promising candidates for future integration into nano-electronics. A key property of these oxides is their ability to form silicates in order to replace the interfacial layer in Si-based complementary metal-oxide field effect transistors. In this work a detailed study of lanthanum lutetium oxide based gate stacks is presented. Special attention is given to the silicate formation at temperatures typical for CMOS processing. The experimental analysis is based on hard x-ray photoemission spectroscopy complemented by standard laboratory experiments as Rutherford backscattering spectrometry and high-resolution transmission electron microscopy. Homogenously distributed La silicate and Lu silicate at the Si interface are proven to form already during gate oxide deposition. During the thermal treatment Si atoms diffuse through the oxide layer towards the TiN metal gate. This mechanism is identified to be promoted via Lu-O bonds, whereby the diffusion of La was found to be less important.

  9. Ultra-nonlocality in density functional theory for photo-emission spectroscopy

    SciTech Connect (OSTI)

    Uimonen, A.-M.; Stefanucci, G.; INFN, Laboratori Nazionali di Frascati, Via E. Fermi 40, 00044 Frascati; European Theoretical Spectroscopy Facility , Louvain-la Neuve ; Leeuwen, R. van; European Theoretical Spectroscopy Facility , Louvain-la Neuve

    2014-05-14

    We derive an exact expression for the photocurrent of photo-emission spectroscopy using time-dependent current density functional theory (TDCDFT). This expression is given as an integral over the Kohn-Sham spectral function renormalized by effective potentials that depend on the exchange-correlation kernel of current density functional theory. We analyze in detail the physical content of this expression by making a connection between the density-functional expression and the diagrammatic expansion of the photocurrent within many-body perturbation theory. We further demonstrate that the density functional expression does not provide us with information on the kinetic energy distribution of the photo-electrons. Such information can, in principle, be obtained from TDCDFT by exactly modeling the experiment in which the photocurrent is split into energy contributions by means of an external electromagnetic field outside the sample, as is done in standard detectors. We find, however, that this procedure produces very nonlocal correlations between the exchange-correlation fields in the sample and the detector.

  10. Photoemission study of the electronic structure and charge density waves of Na?Ti?Sb?O

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Tan, S. Y.; Jiang, J.; Ye, Z. R.; Niu, X. H.; Song, Y.; Zhang, C. L.; Dai, P. C.; Xie, B. P.; Lai, X. C.; Feng, D. L.

    2015-04-30

    The electronic structure of Na?Ti?Sb?O single crystal is studied by photon energy and polarization dependent angle-resolved photoemission spectroscopy (ARPES). The obtained band structure and Fermi surface agree well with the band structure calculation of Na?Ti?Sb?O in the non-magnetic state, which indicates that there is no magnetic order in Na?Ti?Sb?O and the electronic correlation is weak. Polarization dependent ARPES results suggest the multi-band and multi-orbital nature of Na?Ti?Sb?O. Photon energy dependent ARPES results suggest that the electronic structure of Na?Ti?Sb?O is rather two-dimensional. Moreover, we find a density wave energy gap forms below the transition temperature and reaches 65 meV atmore7 K, indicating that Na?Ti?Sb?O is likely a weakly correlated CDW material in the strong electron-phonon interaction regime. (author)less

  11. Photoemission study of the electronic structure and charge density waves of Na?Ti?Sb?O

    SciTech Connect (OSTI)

    Tan, S. Y.; Jiang, J.; Ye, Z. R.; Niu, X. H.; Song, Y.; Zhang, C. L.; Dai, P. C.; Xie, B. P.; Lai, X. C.; Feng, D. L.

    2015-04-30

    The electronic structure of Na?Ti?Sb?O single crystal is studied by photon energy and polarization dependent angle-resolved photoemission spectroscopy (ARPES). The obtained band structure and Fermi surface agree well with the band structure calculation of Na?Ti?Sb?O in the non-magnetic state, which indicates that there is no magnetic order in Na?Ti?Sb?O and the electronic correlation is weak. Polarization dependent ARPES results suggest the multi-band and multi-orbital nature of Na?Ti?Sb?O. Photon energy dependent ARPES results suggest that the electronic structure of Na?Ti?Sb?O is rather two-dimensional. Moreover, we find a density wave energy gap forms below the transition temperature and reaches 65 meV at 7 K, indicating that Na?Ti?Sb?O is likely a weakly correlated CDW material in the strong electron-phonon interaction regime. (author)

  12. Electron mean free path from angle-dependent photoelectron spectroscopy of aerosol particles

    SciTech Connect (OSTI)

    Goldmann, Maximilian; Miguel-Sánchez, Javier; West, Adam H. C.; Yoder, Bruce L.; Signorell, Ruth

    2015-06-14

    We propose angle-resolved photoelectron spectroscopy of aerosol particles as an alternative way to determine the electron mean free path of low energy electrons in solid and liquid materials. The mean free path is obtained from fits of simulated photoemission images to experimental ones over a broad range of different aerosol particle sizes. The principal advantage of the aerosol approach is twofold. First, aerosol photoemission studies can be performed for many different materials, including liquids. Second, the size-dependent anisotropy of the photoelectrons can be exploited in addition to size-dependent changes in their kinetic energy. These finite size effects depend in different ways on the mean free path and thus provide more information on the mean free path than corresponding liquid jet, thin film, or bulk data. The present contribution is a proof of principle employing a simple model for the photoemission of electrons and preliminary experimental data for potassium chloride aerosol particles.

  13. Photoemission Study of the Rare Earth Intermetallic Compounds: RNi2Ge2 (R=Eu, Gd)

    SciTech Connect (OSTI)

    Jongik Park

    2004-12-19

    EuNi{sub 2}Ge{sub 2} and GdNi{sub 2}Ge{sub 2} are two members of the RT{sub 2}X{sub 2} (R = rare earth, T = transition metal and X = Si, Ge) family of intermetallic compounds, which has been studied since the early 1980s. These ternary rare-earth intermetallic compounds with the tetragonal ThCr{sub 2}Si{sub 2} structure are known for their wide variety of magnetic properties, Extensive studies of the RT{sub 2}X{sub 2} series can be found in Refs [ 1,2,3]. The magnetic properties of the rare-earth nickel germanides RNi{sub 2}Ge{sub 2} were recently studied in more detail [4]. The purpose of this dissertation is to investigate the electronic structure (both valence band and shallow core levels) of single crystals of EuNi{sub 2}Ge{sub 2} and GdNi{sub 2}Ge{sub 2} and to check the assumptions that the f electrons are non-interacting and, consequently, the rigid-band model for these crystals would work [11], using synchrotron radiation because, to the best of our knowledge, no photoemission measurements on those have been reported. Photoemission spectroscopy has been widely used to study the detailed electronic structure of metals and alloys, and especially angle-resolved photoemission spectroscopy (ARPES) has proven to be a powerful technique for investigating Fermi surfaces (FSs) of single-crystal compounds.

  14. Conduction band offset at GeO{sub 2}/Ge interface determined by internal photoemission and charge-corrected x-ray photoelectron spectroscopies

    SciTech Connect (OSTI)

    Zhang, W. F.; Nishimula, T.; Nagashio, K.; Kita, K.; Toriumi, A.

    2013-03-11

    We report a consistent conduction band offset (CBO) at a GeO{sub 2}/Ge interface determined by internal photoemission spectroscopy (IPE) and charge-corrected X-ray photoelectron spectroscopy (XPS). IPE results showed that the CBO value was larger than 1.5 eV irrespective of metal electrode and substrate type variance, while an accurate determination of valence band offset (VBO) by XPS requires a careful correction of differential charging phenomena. The VBO value was determined to be 3.60 {+-} 0.2 eV by XPS after charge correction, thus yielding a CBO (1.60 {+-} 0.2 eV) in excellent agreement with the IPE results. Such a large CBO (>1.5 eV) confirmed here is promising in terms of using GeO{sub 2} as a potential passivation layer for future Ge-based scaled CMOS devices.

  15. Direct comparative study on the energy level alignments in unoccupied/occupied states of organic semiconductor/electrode interface by constructing in-situ photoemission spectroscopy and Ar gas cluster ion beam sputtering integrated analysis system

    SciTech Connect (OSTI)

    Yun, Dong-Jin Chung, JaeGwan; Kim, Yongsu; Park, Sung-Hoon; Kim, Seong-Heon; Heo, Sung

    2014-10-21

    Through the installation of electron gun and photon detector, an in-situ photoemission and damage-free sputtering integrated analysis system is completely constructed. Therefore, this system enables to accurately characterize the energy level alignments including unoccupied/occupied molecular orbital (LUMO/HOMO) levels at interface region of organic semiconductor/electrode according to depth position. Based on Ultraviolet Photoemission Spectroscopy (UPS), Inverse Photoemission Spectroscopy (IPES), and reflective electron energy loss spectroscopy, the occupied/unoccupied state of in-situ deposited Tris[4-(carbazol-9-yl)phenyl]amine (TCTA) organic semiconductors on Au (E{sub LUMO}: 2.51?eV and E{sub HOMO}: 1.35?eV) and Ti (E{sub LUMO}: 2.19?eV and E{sub HOMO}: 1.69?eV) electrodes are investigated, and the variation of energy level alignments according to work function of electrode (Au: 4.81?eV and Ti: 4.19?eV) is clearly verified. Subsequently, under the same analysis condition, the unoccupied/occupied states at bulk region of TCTA/Au structures are characterized using different Ar gas cluster ion beam (Ar GCIB) and Ar ion sputtering processes, respectively. While the Ar ion sputtering process critically distorts both occupied and unoccupied states in UPS/IPES spectra, the Ar GCIB sputtering process does not give rise to damage on them. Therefore, we clearly confirm that the in-situ photoemission spectroscopy in combination with Ar GCIB sputtering allows of investigating accurate energy level alignments at bulk/interface region as well as surface region of organic semiconductor/electrode structure.

  16. Optical spectroscopy study of the three-dimensional Dirac semimetal ZrTe5

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Chen, R. Y.; Gu, G. D.; Zhang, S. J.; Schneeloch, J. A.; Zhang, C.; Li, Q.; Wang, N. L.

    2015-08-05

    Three-dimensional (3D) topological Dirac materials have been under intensive study recently. The layered compound ZrTe5 has been suggested to be one such material as a result of transport and angle-resolved photoemission spectroscopy experiments. Here, we perform infrared reflectivity measurements to investigate the underlying physics of this material. The derived optical conductivity increases linearly with frequency below normal interband transitions, which provides optical spectroscopic proof of a 3D Dirac semimetal. In addition, the plasma edge shifts dramatically to lower energy upon temperature cooling, which might be due to the shrinking of the lattice parameters. Additionally, an extremely sharp peak shows upmore » in the frequency-dependent optical conductivity, indicating the presence of a Van Hove singularity in the joint density of state.« less

  17. First Observation of Plasmarons in Graphene

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    First Observation of Plasmarons in Graphene Print An international team of scientists performing angle-resolved photoemission spectroscopy (ARPES) experiments at ALS Beamline 7.0.1...

  18. Observation of a Macroscopically Quantum-Entangled Insulator

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    from Princeton University who studied the electronic structure of insulating alloys of bismuth and antimony by means of angle-resolved photoemission spectroscopy (ARPES) and...

  19. X-ray Imaging Workshop

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    microscopy (PEEM), angle resolved photoemission spectroscopy (ARPES), coherent diffraction imaging, x-ray microscopy, micro-tomography, holographic imaging, and x-ray...

  20. ALS User Meeting Archives

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Alessandra Lanzara, For their groundbreaking work measuring the electronic structure of graphene and the use of high resolution angle-resolved photoemission spectroscopy (ARPES)...

  1. Dependence of Band Renormalization Effect on the Number of Copper-oxide

    Office of Scientific and Technical Information (OSTI)

    Layers in Tl-based Copper-oxide Superconductor using Angle-resolved Photoemission Spectroscopy (Journal Article) | SciTech Connect Dependence of Band Renormalization Effect on the Number of Copper-oxide Layers in Tl-based Copper-oxide Superconductor using Angle-resolved Photoemission Spectroscopy Citation Details In-Document Search Title: Dependence of Band Renormalization Effect on the Number of Copper-oxide Layers in Tl-based Copper-oxide Superconductor using Angle-resolved Photoemission

  2. Electronic Band Dispersion Of CeAg{sub 2}Ge{sub 2} Studied Using Angle

    Office of Scientific and Technical Information (OSTI)

    Resolved Photoemission Spectroscopy (Journal Article) | SciTech Connect Electronic Band Dispersion Of CeAg{sub 2}Ge{sub 2} Studied Using Angle Resolved Photoemission Spectroscopy Citation Details In-Document Search Title: Electronic Band Dispersion Of CeAg{sub 2}Ge{sub 2} Studied Using Angle Resolved Photoemission Spectroscopy Angle resolved photoelectron spectroscopy has been used to determine the electronic band dispersion of CeAg{sub 2}Ge{sub 2} single crystal along the {Gamma}-Z

  3. Quasiparticle dynamics across the full Brillouin zone of Bi2Sr2CaCu2O8+δ

    Office of Scientific and Technical Information (OSTI)

    traced with ultrafast time and angle-resolved photoemission spectroscopy (Journal Article) | SciTech Connect Quasiparticle dynamics across the full Brillouin zone of Bi2Sr2CaCu2O8+δ traced with ultrafast time and angle-resolved photoemission spectroscopy Citation Details In-Document Search Title: Quasiparticle dynamics across the full Brillouin zone of Bi2Sr2CaCu2O8+δ traced with ultrafast time and angle-resolved photoemission spectroscopy A hallmark in the cuprate family of

  4. Rotatable spin-polarized electron source for inverse-photoemission experiments

    SciTech Connect (OSTI)

    Stolwijk, S. D. Wortelen, H.; Schmidt, A. B.; Donath, M.

    2014-01-15

    We present a ROtatable Spin-polarized Electron source (ROSE) for the use in spin- and angle-resolved inverse-photoemission (SR-IPE) experiments. A key feature of the ROSE is a variable direction of the transversal electron beam polarization. As a result, the inverse-photoemission experiment becomes sensitive to two orthogonal in-plane polarization directions, and, for nonnormal electron incidence, to the out-of-plane polarization component. We characterize the ROSE and test its performance on the basis of SR-IPE experiments. Measurements on magnetized Ni films on W(110) serve as a reference to demonstrate the variable spin sensitivity. Moreover, investigations of the unoccupied spin-dependent surface electronic structure of Tl/Si(111) highlight the capability to analyze complex phenomena like spin rotations in momentum space. Essentially, the ROSE opens the way to further studies on complex spin-dependent effects in the field of surface magnetism and spin-orbit interaction at surfaces.

  5. Unusual Layer-Dependent Charge Distribution, Collective Mode...

    Office of Scientific and Technical Information (OSTI)

    resolution angle resolved photoemission spectroscopy study on four-layer self-doped high Tsub c superconductor Basub 2Casub 3Cusub 4Osub 8Fsub 2 (F0234) revealed...

  6. Towards Heavy Fermions in Europium Intermetallic Compounds

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    state in EuNi2P2. The angle-resolved photoemission spectroscopy (ARPES) data for the localized europium 4f6 final states in the rare-earth intermetallic compound EuNi2P2 might...

  7. Coexistence of a pseudogap and a superconducting gap for the...

    Office of Scientific and Technical Information (OSTI)

    - T c superconductor La 2 - x Sr x CuO 4 studied by angle-resolved photoemission spectroscopy Citation Details In-Document Search This content will become publicly available on...

  8. Microsoft Word - Negative_compressibility

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    compressibility (NEC) in a three dimensional spin-orbit correlated metal (Sr 1-x La x ) 3 Ir 2 O 7 , utilizing the high-resolution angle- resolved photoemission spectroscopy...

  9. Time-resolved photoemission apparatus achieving sub-20-meV energy resolution and high stability

    SciTech Connect (OSTI)

    Ishida, Y.; Togashi, T.; Yamamoto, K.; Tanaka, M.; Kiss, T.; Otsu, T.; Kobayashi, Y.; Shin, S.

    2014-12-15

    The paper describes a time- and angle-resolved photoemission apparatus consisting of a hemispherical analyzer and a pulsed laser source. We demonstrate 1.48-eV pump and 5.92-eV probe measurements at the ?10.5-meV and ?240-fs resolutions by use of fairly monochromatic 170-fs pulses delivered from a regeneratively amplified Ti:sapphire laser system operating typically at 250 kHz. The apparatus is capable to resolve the optically filled superconducting peak in the unoccupied states of a cuprate superconductor, Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8+?}. A dataset recorded on Bi(111) surface is also presented. Technical descriptions include the followings: A simple procedure to fine-tune the spatio-temporal overlap of the pump-and-probe beams and their diameters; achieving a long-term stability of the system that enables a normalization-free dataset acquisition; changing the repetition rate by utilizing acoustic optical modulator and frequency-division circuit.

  10. Spectroscopy

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Spectroscopy Spectroscopy Print In spectroscopy experiments, a sample is illuminated with light and the various product particles (electrons, ions, or fluorescent photons) are detected and analyzed.The unifying feature is that some "property" of a material is measured as the x-ray (photon) energy is swept though a range of values. At the most basic level, one measures the absorption, transmission, or reflectivity of a sample as a function of photon energy. Probes that use the vacuum

  11. Spectroscopy

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Spectroscopy Print In spectroscopy experiments, a sample is illuminated with light and the various product particles (electrons, ions, or fluorescent photons) are detected and analyzed.The unifying feature is that some "property" of a material is measured as the x-ray (photon) energy is swept though a range of values. At the most basic level, one measures the absorption, transmission, or reflectivity of a sample as a function of photon energy. Probes that use the vacuum ultraviolet

  12. A medium-energy photoemission and ab-initio investigation of cubic yttria-stabilised zirconia

    SciTech Connect (OSTI)

    Cousland, G. P.; Cui, X. Y.; Smith, A. E.; Stampfl, C. M.; Wong, L.; Tayebjee, M.; Yu, D.; Triani, G.; Evans, P. J.; Ruppender, H.-J.; Jang, L.-Y.; Stampfl, A. P. J.

    2014-04-14

    Experimental and theoretical investigations into the electronic properties and structure of cubic yttria-stabilized zirconia are presented. Medium-energy x-ray photoemission spectroscopy measurements have been carried out for material with a concentration of 8-9?mol.?% yttria. Resonant photoemission spectra are obtained for a range of photon energies that traverse the L2 absorption edge for both zirconium and yttrium. Through correlation with results from density-functional theory (DFT) calculations, based on structural models proposed in the literature, we assign photoemission peaks appearing in the spectra to core lines and Auger transitions. An analysis of the core level features enables the identification of shifts in the core level energies due to different local chemical environments of the constituent atoms. In general, each core line feature can be decomposed into three contributions, with associated energy shifts. Their identification with results of DFT calculations carried out for proposed atomic structures, lends support to these structural models. The experimental results indicate a multi-atom resonant photoemission effect between nearest-neighbour oxygen and yttrium atoms. Near-edge x-ray absorption fine structure spectra for zirconium and yttrium are also presented, which correlate well with calculated Zr- and Y-4d electron partial density-of-states and with Auger electron peak area versus photon energy curve.

  13. Coexistence of a pseudogap and a superconducting gap for the high - T c

    Office of Scientific and Technical Information (OSTI)

    superconductor La 2 - x Sr x CuO 4 studied by angle-resolved photoemission spectroscopy (Journal Article) | DOE PAGES Coexistence of a pseudogap and a superconducting gap for the high - T c superconductor La 2 - x Sr x CuO 4 studied by angle-resolved photoemission spectroscopy This content will become publicly available on January 18, 2017 « Prev Next » Title: Coexistence of a pseudogap and a superconducting gap for the high - T c superconductor La 2 - x Sr x CuO 4 studied by

  14. Coexistence of a pseudogap and a superconducting gap for the high - T c

    Office of Scientific and Technical Information (OSTI)

    superconductor La 2 - x Sr x CuO 4 studied by angle-resolved photoemission spectroscopy (Journal Article) | SciTech Connect Coexistence of a pseudogap and a superconducting gap for the high - T c superconductor La 2 - x Sr x CuO 4 studied by angle-resolved photoemission spectroscopy Citation Details In-Document Search This content will become publicly available on January 18, 2017 Title: Coexistence of a pseudogap and a superconducting gap for the high - T c superconductor La 2 - x Sr x CuO

  15. An In Situ Study of the Martensitic Transformation in Shape Memory Alloys Using Photoemission Electron Microscopy

    SciTech Connect (OSTI)

    Cai, Mingdong; Langford, Stephen C.; Dickinson, J. T.; Xiong, Gang; Droubay, Timothy C.; Joly, Alan G.; Beck, Kenneth M.; Hess, Wayne P.

    2007-04-15

    Thermally-induced martensitic phase transformations in polycrystalline CuZnAl and thin-film NiTiCu shape memory alloys were probed using photoemission electron microscopy (PEEM). Ultra-violet photoelectron spectroscopy shows a reversible change in the apparent work function during transformation, presumably due to the contrasting surface electronic structures of the martensite and austenite phases. In situ PEEM images provide information on the spatial distribution of these phases and the evolution of the surface microstructure during transformation. PEEM offers considerable potential for improving our understanding of martensitic transformations in shape memory alloys in real time.

  16. Multiatom Resonant Photoemission: Theory and Systematics

    SciTech Connect (OSTI)

    Garcia de Abajo, F.J.; Fadley, C.S.; Van Hove, M.A.; Garcia de Abajo, F.J.

    1999-05-01

    A first-principles calculation of the recently discovered interatomic multiatom resonant photoemission (MARPE) effect is presented. In this phenomenon, core photoelectron intensities are enhanced when the photon energy is tuned to a core-level absorption edge of nonidentical neighboring atoms, thus enabling direct determination of near-neighbor atomic identities. Both the multiatom character of MARPE and retardation effects in the photon and electron interactions in the resonant channel are shown to be crucial. Measured peak-intensity enhancements of 40{percent} in MnO and spectral shapes similar to the corresponding x-ray absorption profiles are well reproduced by this theory. {copyright} {ital 1999} {ital The American Physical Society}

  17. Electronic structure and the x-ray photoemission spectrum of the Kondo-dense compound UCu{sub 5}Al

    SciTech Connect (OSTI)

    Chelkowska, G.; Morkowski, J. A.; Szajek, A.; Troc, R.

    2001-08-15

    UCu{sub 5}Al belongs to a class of Kondo-dense compounds. The electronic structure has been studied by combining x-ray photoemission spectroscopy results with those obtained in the band structure calculation. The latter was carried out by using the tight-binding linear muffin-tin orbital method in the atomic sphere approximation. Reasonable agreement between the experimental and calculated data has been achieved. A complex satellite structure observed in the core-level spectra may suggest that the uranium atoms have some mixed valence character, as is the case of other uranium heavy fermion systems.

  18. Accessing Phonon Polaritons in Hyperbolic Crystals by Angle-Resolved...

    Office of Scientific and Technical Information (OSTI)

    This content will become publicly available on August 20, 2016 Title: Accessing Phonon ... become publicly available on August 20, 2016 Publisher's Version of Record 10.1103...

  19. X-ray photoemission electron microscopy for the study of semiconductor materials

    SciTech Connect (OSTI)

    Anders, S.; Stammler, T.; Padmore, H.; Terminello, L.J.; Jankowski, A.F.; Stohr, J.; Diaz, J.; Cossy-Gantner, A.

    1998-03-01

    Photoemission Electron Microscopy (PEEM) using X-rays is a novel combination of two established materials analysis techniques--PEEM using UV light, and Near Edge X-ray Absorption Fine Structure (NEXAFS) spectroscopy. This combination allows the study of elemental composition and bonding structure of the sample by NEXAFS spectroscopy with a high spatial resolution given by the microscope. A simple, two lens, 10 kV operation voltage PEEM has been used at the Stanford Synchrotron Radiation Laboratory and at the Advanced Light Source (ALS) in Berkeley to study various problems including materials of interest for the semiconductor industry. In the present paper the authors give a short overview over the method and the instrument which was used, and describe in detail a number of applications. These applications include the study of the different phases of titanium disilicide, various phases of boron nitride, and the analysis of small particles. A brief outlook is given on possible new fields of application of the PEEM technique, and the development of new PEEM instruments.

  20. Revisiting Photoemission and Inverse Photoemission Spectra of Nickel Oxide from First Principles: Implications for Solar Energy Conversion

    SciTech Connect (OSTI)

    Alidoust, Nima; Toroker, Maytal; Carter, Emily A.

    2014-07-17

    We use two different ab initio quantum mechanics methods, complete active space self-consistent field theory applied to electrostatically embedded clusters and periodic many-body G?W? calculations, to reanalyze the states formed in nickel(II) oxide upon electron addition and ionization. In agreement with interpretations of earlier measurements, we find that the valence and conduction band edges consist of oxygen and nickel states, respectively. However, contrary to conventional wisdom, we find that the oxygen states of the valence band edge are localized whereas the nickel states at the conduction band edge are delocalized. We argue that these characteristics may lead to low electron-hole recombination and relatively efficient electron transport, which, coupled with band gap engineering, could produce higher solar energy conversion efficiency compared to that of other transition-metal oxides. Both methods find a photoemission/inverse-photoemission gap of 3.6-3.9 eV, in good agreement with the experimental range, lending credence to our analysis of the electronic structure of NiO.

  1. Two-Photon Photoemission Study of the Coverage-Dependent Electronic...

    Office of Scientific and Technical Information (OSTI)

    SciTech Connect Search Results Journal Article: Two-Photon Photoemission Study of the Coverage-Dependent Electronic Structure of Chemisorbed Alkali Atoms on a Ag(111) Surface ...

  2. Standing-wave excited soft x-ray photoemission microscopy: application...

    Office of Scientific and Technical Information (OSTI)

    Standing-wave excited soft x-ray photoemission microscopy: application to Co microdot magnetic arrays Citation Details In-Document Search Title: Standing-wave excited soft x-ray...

  3. Controlling Graphene's Electronic Structure

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    as bandgap engineering. While bandgap engineering is the basis of semiconductor technology, it is only now being applied to graphene. Using angle-resolved photoemission...

  4. Two-Photon Photoemission Study of the Coverage-Dependent Electronic

    Office of Scientific and Technical Information (OSTI)

    Structure of Chemisorbed Alkali Atoms on a Ag(111) Surface (Journal Article) | SciTech Connect SciTech Connect Search Results Journal Article: Two-Photon Photoemission Study of the Coverage-Dependent Electronic Structure of Chemisorbed Alkali Atoms on a Ag(111) Surface Citation Details In-Document Search Title: Two-Photon Photoemission Study of the Coverage-Dependent Electronic Structure of Chemisorbed Alkali Atoms on a Ag(111) Surface We report a systematic investigation of the electronic

  5. Nature and Origin of the Cuprate Pseudogap

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Nature and Origin of the Cuprate Pseudogap Print The workings of high-temperature superconductive (HTSC) materials are a mystery wrapped in an enigma. However, a team of researchers from the ALS, Brookhaven National Laboratory, and Cornell University has taken a major step in understanding part of this mystery-the nature and origin of the pseudogap. Using angle-resolved photoemission spectroscopy (ARPES) and scanning tunneling microscopy (STM), they have determined the electronic structure of

  6. Anisotropic scattering rate in Fe-substituted Bi2Sr2Ca(Cu1-xFex)2O8+δ

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Naamneh, M.; Lubashevsky, Y.; Lahoud, E.; Gu, G.; Kanigel, A.

    2015-05-27

    We measured the electronic structure of Fe substituted Bi2212 using Angle Resolved Photoemission Spectroscopy (ARPES). We find that the substitution does not change the momentum dependence of the superconducting gap but induces a very anisotropic enhancement of the scattering rate. A comparison of the effect of Fe substitution to that of Zn substitution suggests that the Fe reduces Tc so effectively because it supresses very strongly the coherence weight around the anti-nodes.

  7. Weyl Fermions Discovered After 85 Years

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Weyl Fermions Discovered After 85 Years Print An international team led by Princeton University scientists has discovered an elusive massless particle first theorized 85 years ago: the Weyl fermion. It was detected as an emergent quasiparticle in synthetic crystals of the semimetal, tantalum arsenide (TaAs). Using angle-resolved photoemission spectroscopy (ARPES), the researchers studied the surface and bulk band structure of TaAs. The results exhibit the features-cones, nodes, and arcs-that

  8. Weyl Fermions Discovered After 85 Years

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Weyl Fermions Discovered After 85 Years Print An international team led by Princeton University scientists has discovered an elusive massless particle first theorized 85 years ago: the Weyl fermion. It was detected as an emergent quasiparticle in synthetic crystals of the semimetal, tantalum arsenide (TaAs). Using angle-resolved photoemission spectroscopy (ARPES), the researchers studied the surface and bulk band structure of TaAs. The results exhibit the features-cones, nodes, and arcs-that

  9. Weyl Fermions Discovered After 85 Years

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Weyl Fermions Discovered After 85 Years Weyl Fermions Discovered After 85 Years Print Wednesday, 09 December 2015 00:00 An international team led by Princeton University scientists has discovered an elusive massless particle first theorized 85 years ago: the Weyl fermion. It was detected as an emergent quasiparticle in synthetic crystals of the semimetal, tantalum arsenide (TaAs). Using angle-resolved photoemission spectroscopy (ARPES), the researchers studied the surface and bulk band structure

  10. An Iridate with Fermi Arcs

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    An Iridate with Fermi Arcs Print Researchers have discovered that "Fermi arcs," which are much-debated features found in the electronic structure of high-temperature superconducting (HTSC) cuprates, can also be found in an iridate (iridium oxide) compound. At the ALS, the researchers observed the electronic structure of strontium iridate as it evolved through different doping levels and temperatures by using angle-resolved photoemission spectroscopy (ARPES) with in situ electron doping

  11. An Iridate with Fermi Arcs

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    An Iridate with Fermi Arcs Print Researchers have discovered that "Fermi arcs," which are much-debated features found in the electronic structure of high-temperature superconducting (HTSC) cuprates, can also be found in an iridate (iridium oxide) compound. At the ALS, the researchers observed the electronic structure of strontium iridate as it evolved through different doping levels and temperatures by using angle-resolved photoemission spectroscopy (ARPES) with in situ electron doping

  12. An Iridate with Fermi Arcs

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    An Iridate with Fermi Arcs Print Researchers have discovered that "Fermi arcs," which are much-debated features found in the electronic structure of high-temperature superconducting (HTSC) cuprates, can also be found in an iridate (iridium oxide) compound. At the ALS, the researchers observed the electronic structure of strontium iridate as it evolved through different doping levels and temperatures by using angle-resolved photoemission spectroscopy (ARPES) with in situ electron doping

  13. Nature and Origin of the Cuprate Pseudogap

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Nature and Origin of the Cuprate Pseudogap Print The workings of high-temperature superconductive (HTSC) materials are a mystery wrapped in an enigma. However, a team of researchers from the ALS, Brookhaven National Laboratory, and Cornell University has taken a major step in understanding part of this mystery-the nature and origin of the pseudogap. Using angle-resolved photoemission spectroscopy (ARPES) and scanning tunneling microscopy (STM), they have determined the electronic structure of

  14. Nature and Origin of the Cuprate Pseudogap

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Nature and Origin of the Cuprate Pseudogap Print The workings of high-temperature superconductive (HTSC) materials are a mystery wrapped in an enigma. However, a team of researchers from the ALS, Brookhaven National Laboratory, and Cornell University has taken a major step in understanding part of this mystery-the nature and origin of the pseudogap. Using angle-resolved photoemission spectroscopy (ARPES) and scanning tunneling microscopy (STM), they have determined the electronic structure of

  15. Nature and Origin of the Cuprate Pseudogap

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Nature and Origin of the Cuprate Pseudogap Print The workings of high-temperature superconductive (HTSC) materials are a mystery wrapped in an enigma. However, a team of researchers from the ALS, Brookhaven National Laboratory, and Cornell University has taken a major step in understanding part of this mystery-the nature and origin of the pseudogap. Using angle-resolved photoemission spectroscopy (ARPES) and scanning tunneling microscopy (STM), they have determined the electronic structure of

  16. Nature and Origin of the Cuprate Pseudogap

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Nature and Origin of the Cuprate Pseudogap Print The workings of high-temperature superconductive (HTSC) materials are a mystery wrapped in an enigma. However, a team of researchers from the ALS, Brookhaven National Laboratory, and Cornell University has taken a major step in understanding part of this mystery-the nature and origin of the pseudogap. Using angle-resolved photoemission spectroscopy (ARPES) and scanning tunneling microscopy (STM), they have determined the electronic structure of

  17. Nature and Origin of the Cuprate Pseudogap

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Nature and Origin of the Cuprate Pseudogap Nature and Origin of the Cuprate Pseudogap Print Wednesday, 30 May 2007 00:00 The workings of high-temperature superconductive (HTSC) materials are a mystery wrapped in an enigma. However, a team of researchers from the ALS, Brookhaven National Laboratory, and Cornell University has taken a major step in understanding part of this mystery-the nature and origin of the pseudogap. Using angle-resolved photoemission spectroscopy (ARPES) and scanning

  18. News Item

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Newly Developed Tool Enables Remote Researchers to Take a Deeper Look at Interfaces An international team of researchers working at the Advanced Light Source (ALS) and remotely operating instruments at the National Center for Electron Microcopy (NCEM) via the Energy Sciences Network (ESnet) recently developed a new technique called Standing Wave Angle-Resolved Photoemission Spectroscopy, or SWARPES, to unlock the vast potential of metal oxide interfaces, especially those buried in subsurface

  19. Weyl Fermions Discovered After 85 Years

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Weyl Fermions Discovered After 85 Years Print An international team led by Princeton University scientists has discovered an elusive massless particle first theorized 85 years ago: the Weyl fermion. It was detected as an emergent quasiparticle in synthetic crystals of the semimetal, tantalum arsenide (TaAs). Using angle-resolved photoemission spectroscopy (ARPES), the researchers studied the surface and bulk band structure of TaAs. The results exhibit the features-cones, nodes, and arcs-that

  20. Weyl Fermions Discovered After 85 Years

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Weyl Fermions Discovered After 85 Years Print An international team led by Princeton University scientists has discovered an elusive massless particle first theorized 85 years ago: the Weyl fermion. It was detected as an emergent quasiparticle in synthetic crystals of the semimetal, tantalum arsenide (TaAs). Using angle-resolved photoemission spectroscopy (ARPES), the researchers studied the surface and bulk band structure of TaAs. The results exhibit the features-cones, nodes, and arcs-that

  1. Weyl Fermions Discovered After 85 Years

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Weyl Fermions Discovered After 85 Years Print An international team led by Princeton University scientists has discovered an elusive massless particle first theorized 85 years ago: the Weyl fermion. It was detected as an emergent quasiparticle in synthetic crystals of the semimetal, tantalum arsenide (TaAs). Using angle-resolved photoemission spectroscopy (ARPES), the researchers studied the surface and bulk band structure of TaAs. The results exhibit the features-cones, nodes, and arcs-that

  2. Weyl Fermions Discovered After 85 Years

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Weyl Fermions Discovered After 85 Years Print An international team led by Princeton University scientists has discovered an elusive massless particle first theorized 85 years ago: the Weyl fermion. It was detected as an emergent quasiparticle in synthetic crystals of the semimetal, tantalum arsenide (TaAs). Using angle-resolved photoemission spectroscopy (ARPES), the researchers studied the surface and bulk band structure of TaAs. The results exhibit the features-cones, nodes, and arcs-that

  3. First Direct Observation of Spinons and Holons

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    First Direct Observation of Spinons and Holons Print Spin and charge are inseparable traits of an electron, but in one-dimensional solids, a 40-year-old theory predicts their separation into "collective" modes-as independent excitation quanta called spinons and holons. Angle-resolved photoemission spectroscopy (ARPES) should provide the most direct evidence of this spin-charge separation, as the single quasiparticle peak splits into a spinon-holon two-peak structure. However, despite

  4. First Observation of Plasmarons in Graphene

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    First Observation of Plasmarons in Graphene Print An international team of scientists performing angle-resolved photoemission spectroscopy (ARPES) experiments at ALS Beamline 7.0.1 have found that composite particles called plasmarons play a vital role in determining graphene's properties. A plasmaron consists of a charge carrier (electron or hole) coupled with a plasmon-an electron density wave. Although plasmarons were proposed theoretically in the late 1960s, and indirect evidence of them has

  5. First Observation of Plasmarons in Graphene

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    First Observation of Plasmarons in Graphene Print An international team of scientists performing angle-resolved photoemission spectroscopy (ARPES) experiments at ALS Beamline 7.0.1 have found that composite particles called plasmarons play a vital role in determining graphene's properties. A plasmaron consists of a charge carrier (electron or hole) coupled with a plasmon-an electron density wave. Although plasmarons were proposed theoretically in the late 1960s, and indirect evidence of them has

  6. First Direct Observation of Spinons and Holons

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    First Direct Observation of Spinons and Holons Print Spin and charge are inseparable traits of an electron, but in one-dimensional solids, a 40-year-old theory predicts their separation into "collective" modes-as independent excitation quanta called spinons and holons. Angle-resolved photoemission spectroscopy (ARPES) should provide the most direct evidence of this spin-charge separation, as the single quasiparticle peak splits into a spinon-holon two-peak structure. However, despite

  7. First Direct Observation of Spinons and Holons

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    First Direct Observation of Spinons and Holons Print Spin and charge are inseparable traits of an electron, but in one-dimensional solids, a 40-year-old theory predicts their separation into "collective" modes-as independent excitation quanta called spinons and holons. Angle-resolved photoemission spectroscopy (ARPES) should provide the most direct evidence of this spin-charge separation, as the single quasiparticle peak splits into a spinon-holon two-peak structure. However, despite

  8. First Direct Observation of Spinons and Holons

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    First Direct Observation of Spinons and Holons First Direct Observation of Spinons and Holons Print Wednesday, 30 August 2006 00:00 Spin and charge are inseparable traits of an electron, but in one-dimensional solids, a 40-year-old theory predicts their separation into "collective" modes-as independent excitation quanta called spinons and holons. Angle-resolved photoemission spectroscopy (ARPES) should provide the most direct evidence of this spin-charge separation, as the single

  9. First Observation of Plasmarons in Graphene

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    First Observation of Plasmarons in Graphene Print An international team of scientists performing angle-resolved photoemission spectroscopy (ARPES) experiments at ALS Beamline 7.0.1 have found that composite particles called plasmarons play a vital role in determining graphene's properties. A plasmaron consists of a charge carrier (electron or hole) coupled with a plasmon-an electron density wave. Although plasmarons were proposed theoretically in the late 1960s, and indirect evidence of them has

  10. First Observation of Plasmarons in Graphene

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    First Observation of Plasmarons in Graphene Print An international team of scientists performing angle-resolved photoemission spectroscopy (ARPES) experiments at ALS Beamline 7.0.1 have found that composite particles called plasmarons play a vital role in determining graphene's properties. A plasmaron consists of a charge carrier (electron or hole) coupled with a plasmon-an electron density wave. Although plasmarons were proposed theoretically in the late 1960s, and indirect evidence of them has

  11. First Observation of Plasmarons in Graphene

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    First Observation of Plasmarons in Graphene Print An international team of scientists performing angle-resolved photoemission spectroscopy (ARPES) experiments at ALS Beamline 7.0.1 have found that composite particles called plasmarons play a vital role in determining graphene's properties. A plasmaron consists of a charge carrier (electron or hole) coupled with a plasmon-an electron density wave. Although plasmarons were proposed theoretically in the late 1960s, and indirect evidence of them has

  12. First Observation of Plasmarons in Graphene

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    First Observation of Plasmarons in Graphene Print An international team of scientists performing angle-resolved photoemission spectroscopy (ARPES) experiments at ALS Beamline 7.0.1 have found that composite particles called plasmarons play a vital role in determining graphene's properties. A plasmaron consists of a charge carrier (electron or hole) coupled with a plasmon-an electron density wave. Although plasmarons were proposed theoretically in the late 1960s, and indirect evidence of them has

  13. First Observation of Plasmarons in Graphene

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    First Observation of Plasmarons in Graphene First Observation of Plasmarons in Graphene Print Wednesday, 30 June 2010 00:00 An international team of scientists performing angle-resolved photoemission spectroscopy (ARPES) experiments at ALS Beamline 7.0.1 have found that composite particles called plasmarons play a vital role in determining graphene's properties. A plasmaron consists of a charge carrier (electron or hole) coupled with a plasmon-an electron density wave. Although plasmarons were

  14. An Iridate with Fermi Arcs

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    An Iridate with Fermi Arcs Print Researchers have discovered that "Fermi arcs," which are much-debated features found in the electronic structure of high-temperature superconducting (HTSC) cuprates, can also be found in an iridate (iridium oxide) compound. At the ALS, the researchers observed the electronic structure of strontium iridate as it evolved through different doping levels and temperatures by using angle-resolved photoemission spectroscopy (ARPES) with in situ electron doping

  15. An Iridate with Fermi Arcs

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    An Iridate with Fermi Arcs Print Researchers have discovered that "Fermi arcs," which are much-debated features found in the electronic structure of high-temperature superconducting (HTSC) cuprates, can also be found in an iridate (iridium oxide) compound. At the ALS, the researchers observed the electronic structure of strontium iridate as it evolved through different doping levels and temperatures by using angle-resolved photoemission spectroscopy (ARPES) with in situ electron doping

  16. Synchrotron x-ray photoemission study of soft x-ray processed ultrathin glycine-water ice films

    SciTech Connect (OSTI)

    Tzvetkov, George; Netzer, Falko P.

    2011-05-28

    Ultrathin glycine-water ice films have been prepared in ultrahigh vacuum by condensation of H{sub 2}O and glycine at 90 K on single crystalline alumina surfaces and processed by soft x-ray (610 eV) exposure for up to 60 min. The physicochemical changes in the films were monitored using synchrotron x-ray photoemission spectroscopy. Two films with different amounts of H{sub 2}O have been considered in order to evaluate the influence of the water ice content on the radiation-induced effects. The analysis of C1s, N1s, and O1s spectral regions together with the changes in the valence band spectra indicates that amino acid degradation occurs fast mainly via decarboxylation and deamination of pristine molecules. Enrichment of the x-ray exposed surfaces with fragments with carbon atoms without strong electronegative substituents (C-C and C-H) is documented as well. In the thinner glycine-water ice film (six layers of glycine + six layers of water) the 3D ice suffers strongly from the x-rays and is largely removed from the sample. The rate of photodecomposition of glycine in this film is about 30% higher than for glycine in the thicker film (6 layers of glycine + 60 layers of water). The photoemission results suggest that the destruction of amino acid molecules is caused by the direct interaction with the radiation and that no chemical attack of glycine by the species released by water radiolysis is detected.

  17. Anomalous temperature dependence in valence band spectra: A resonant photoemission study of layered perovskite Sr{sub 2}CoO{sub 4}

    SciTech Connect (OSTI)

    Pandey, Pankaj K.; Choudhary, R. J. Phase, D. M.

    2014-05-05

    Valence band spectra (VBS) and its modification across Curie temperature (T{sub C}) of Sr{sub 2}CoO{sub 4} thin film are studied using resonant photoemission spectroscopy. It is found that VBS mainly consists of hybridized states of Co-3d t{sub 2g}e{sub g} and O-2p; however, Co-3d e{sub g} states show its prominence only in the ferromagnetic temperature regime. Below T{sub C}, spectral weight transfer takes place anomalously from high binding energy (B.E.) region to low B.E. region, signifying the enhanced intermediate or low spin state Co{sup 4+} ions. It is suggested that spin-lattice coupling and many-body effects in Sr{sub 2}CoO{sub 4} derived from the strong electron correlations lead to such temperature dependence of VBS.

  18. Optimisation of NSLS-II Blade X-ray Beam Position Monitors: from Photoemission type to Diamond Detector

    SciTech Connect (OSTI)

    ILINSKI P.

    2012-07-10

    Optimisation of blade type x-ray beam position monitors (XBPM) was performed for NSLS-II undulator IVU20. Blade material, con and #64257;guration and operation principle was analysed in order to improve XBPM performance. Optimisation is based on calculation of the XBPM signal spatial distribution. Along with standard photoemission type XBPM a Diamond Detector Blades (DDB) were analysed as blades for XBPMs. DDB XBPMs can help to overcome drawbacks of the photoemission blade XBPMs.

  19. Momentum-resolved photoemission of the Kondo peak in an ordered Ce-containing alloy

    SciTech Connect (OSTI)

    Garnier, M.; Purdie, D.; Breuer, K.; Hengsberger, M.; Baer, Y.

    1997-11-01

    A comparison of uv-photoemission spectra recorded from the surface alloys Pt(111)({radical}(3){times}{radical}(3))R30{degree}Ce and Pt(111)(2{times}2)La allows the contribution from the 4f electrons to be seen easily. The valence-band structure of these two surfaces is very similar, and the most obvious 4f contribution in high-resolution photoemission spectra of the Ce-containing alloy is the tail of the Kondo peak cut at E{sub F}. Within the limits of our measurement, no dispersion of this feature in the occupied regime is detected. The Kondo peak displays a marked intensity dependence on the emission angle, suggesting that hybridization is present in only a limited part of reciprocal space. The temperature dependence of this near-E{sub F} feature supports this interpretation. {copyright} {ital 1997} {ital The American Physical Society}

  20. Interference of spin states in resonant photoemission induced by circularly polarized light from magnetized Gd

    SciTech Connect (OSTI)

    Mueller, N.; Khalil, T.; Pohl, M.; Uphues, T.; Heinzmann, U.; Polcik, M.; Rader, O.; Heigl, F.; Starke, K.; Fritzsche, S.; Kabachnik, N. M.

    2006-10-15

    We have observed the spin-state interference by measuring the photoelectron spin polarization in the resonant preedge 4d{yields}4f photoemission from magnetized Gd. The photoemission is induced by circularly polarized light which determines one preferential direction of electron spin orientation due to polarization transfer and spin-orbit interaction. Another direction perpendicular to the first one is determined by the target electron spin orientation connected with the target magnetization. We have measured the component of spin polarization perpendicular to those two directions which can only appear due to spin-state interference which implies coherence of the spin states produced by the two mechanisms of the photoelectron spin polarization.

  1. Beamline 4.0.3

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    3 Print High-resolution spectroscopy of complex materials (MERLIN) Endstations: 4.0.3.1: High-resolution inelastic scattering (MERIXS) 4.0.3.2: Angle-resolved photoemission spectroscopy (ARPES) GENERAL BEAMLINE INFORMATION Operational 2011 Source characteristics 9.0-cm-period quasiperiodic elliptical polarization undulator (EPU9) Energy range 9eV-120eV with current gratings Monochromator Variable-included-angle spherical grating monochromator (SGM) Calculated flux (1.9 GeV, 400 mA) 1012

  2. Beamline 4.0.3

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    3 Print High-resolution spectroscopy of complex materials (MERLIN) Endstations: 4.0.3.1: High-resolution inelastic scattering (MERIXS) 4.0.3.2: Angle-resolved photoemission spectroscopy (ARPES) GENERAL BEAMLINE INFORMATION Operational 2011 Source characteristics 9.0-cm-period quasiperiodic elliptical polarization undulator (EPU9) Energy range 9eV-120eV with current gratings Monochromator Variable-included-angle spherical grating monochromator (SGM) Calculated flux (1.9 GeV, 400 mA) 1012

  3. Beamline 4.0.3

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    3 Print High-resolution spectroscopy of complex materials (MERLIN) Endstations: 4.0.3.1: High-resolution inelastic scattering (MERIXS) 4.0.3.2: Angle-resolved photoemission spectroscopy (ARPES) GENERAL BEAMLINE INFORMATION Operational 2011 Source characteristics 9.0-cm-period quasiperiodic elliptical polarization undulator (EPU9) Energy range 9eV-120eV with current gratings Monochromator Variable-included-angle spherical grating monochromator (SGM) Calculated flux (1.9 GeV, 400 mA) 1012

  4. Beamline 4.0.3

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Beamline 4.0.3 Print High-resolution spectroscopy of complex materials (MERLIN) Endstations: 4.0.3.1: High-resolution inelastic scattering (MERIXS) 4.0.3.2: Angle-resolved photoemission spectroscopy (ARPES) GENERAL BEAMLINE INFORMATION Operational 2011 Source characteristics 9.0-cm-period quasiperiodic elliptical polarization undulator (EPU9) Energy range 9eV-120eV with current gratings Monochromator Variable-included-angle spherical grating monochromator (SGM) Calculated flux (1.9 GeV, 400 mA)

  5. Beamline 4.0.3

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Beamline 4.0.3 Print High-resolution spectroscopy of complex materials (MERLIN) Endstations: 4.0.3.1: High-resolution inelastic scattering (MERIXS) 4.0.3.2: Angle-resolved photoemission spectroscopy (ARPES) GENERAL BEAMLINE INFORMATION Operational 2011 Source characteristics 9.0-cm-period quasiperiodic elliptical polarization undulator (EPU9) Energy range 9eV-120eV with current gratings Monochromator Variable-included-angle spherical grating monochromator (SGM) Calculated flux (1.9 GeV, 400 mA)

  6. Beamline 4.0.3

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Beamline 4.0.3 Print High-resolution spectroscopy of complex materials (MERLIN) Endstations: 4.0.3.1: High-resolution inelastic scattering (MERIXS) 4.0.3.2: Angle-resolved photoemission spectroscopy (ARPES) GENERAL BEAMLINE INFORMATION Operational 2011 Source characteristics 9.0-cm-period quasiperiodic elliptical polarization undulator (EPU9) Energy range 9eV-120eV with current gratings Monochromator Variable-included-angle spherical grating monochromator (SGM) Calculated flux (1.9 GeV, 400 mA)

  7. Beamline 4.0.3

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    3 Print High-resolution spectroscopy of complex materials (MERLIN) Endstations: 4.0.3.1: High-resolution inelastic scattering (MERIXS) 4.0.3.2: Angle-resolved photoemission spectroscopy (ARPES) GENERAL BEAMLINE INFORMATION Operational 2011 Source characteristics 9.0-cm-period quasiperiodic elliptical polarization undulator (EPU9) Energy range 9eV-120eV with current gratings Monochromator Variable-included-angle spherical grating monochromator (SGM) Calculated flux (1.9 GeV, 400 mA) 1012

  8. Beamline 4.0.3

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    3 Print High-resolution spectroscopy of complex materials (MERLIN) Endstations: 4.0.3.1: High-resolution inelastic scattering (MERIXS) 4.0.3.2: Angle-resolved photoemission spectroscopy (ARPES) GENERAL BEAMLINE INFORMATION Operational 2011 Source characteristics 9.0-cm-period quasiperiodic elliptical polarization undulator (EPU9) Energy range 9eV-120eV with current gratings Monochromator Variable-included-angle spherical grating monochromator (SGM) Calculated flux (1.9 GeV, 400 mA) 1012

  9. Beamline 4.0.3

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    3 Print High-resolution spectroscopy of complex materials (MERLIN) Endstations: 4.0.3.1: High-resolution inelastic scattering (MERIXS) 4.0.3.2: Angle-resolved photoemission spectroscopy (ARPES) GENERAL BEAMLINE INFORMATION Operational 2011 Source characteristics 9.0-cm-period quasiperiodic elliptical polarization undulator (EPU9) Energy range 9eV-120eV with current gratings Monochromator Variable-included-angle spherical grating monochromator (SGM) Calculated flux (1.9 GeV, 400 mA) 1012

  10. Beamline 4.0.3

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    3 Print High-resolution spectroscopy of complex materials (MERLIN) Endstations: 4.0.3.1: High-resolution inelastic scattering (MERIXS) 4.0.3.2: Angle-resolved photoemission spectroscopy (ARPES) GENERAL BEAMLINE INFORMATION Operational 2011 Source characteristics 9.0-cm-period quasiperiodic elliptical polarization undulator (EPU9) Energy range 9eV-120eV with current gratings Monochromator Variable-included-angle spherical grating monochromator (SGM) Calculated flux (1.9 GeV, 400 mA) 1012

  11. X-ray photoemission analysis of chemically modified TlBr surfaces for improved radiation detectors

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Nelson, A. J.; Voss, L. F.; Beck, P. R.; Graff, R. T.; Conway, A. M.; Nikolic, R. J.; Payne, S. A.; Lee, J. -S.; Kim, H.; Cirignano, L.; et al

    2013-01-12

    We subjected device-grade TlBr to various chemical treatments used in room temperature radiation detector fabrication to determine the resulting surface composition and electronic structure. As-polished TlBr was treated separately with HCl, SOCl2, Br:MeOH and HF solutions. High-resolution photoemission measurements on the valence band electronic structure and Tl 4f, Br 3d, Cl 2p and S 2p core lines were used to evaluate surface chemistry and shallow heterojunction formation. Surface chemistry and valence band electronic structure were correlated with the goal of optimizing the long-term stability and radiation response.

  12. Universal versus Materials-Dependent Two-Gap Behaviour of the High-Tc

    Office of Scientific and Technical Information (OSTI)

    Cuprate Superconductors: Angle-Resolved Photoemission Study of La2-xSrxCuO4 (Journal Article) | SciTech Connect Universal versus Materials-Dependent Two-Gap Behaviour of the High-Tc Cuprate Superconductors: Angle-Resolved Photoemission Study of La2-xSrxCuO4 Citation Details In-Document Search Title: Universal versus Materials-Dependent Two-Gap Behaviour of the High-Tc Cuprate Superconductors: Angle-Resolved Photoemission Study of La2-xSrxCuO4 We have investigated the doping and temperature

  13. Universal versus Materials-Dependent Two-Gap Behaviour of the High-Tc

    Office of Scientific and Technical Information (OSTI)

    Cuprate Superconductors: Angle-Resolved Photoemission Study of La2-xSrxCuO4 (Journal Article) | SciTech Connect Universal versus Materials-Dependent Two-Gap Behaviour of the High-Tc Cuprate Superconductors: Angle-Resolved Photoemission Study of La2-xSrxCuO4 Citation Details In-Document Search Title: Universal versus Materials-Dependent Two-Gap Behaviour of the High-Tc Cuprate Superconductors: Angle-Resolved Photoemission Study of La2-xSrxCuO4 × You are accessing a document from the

  14. Solar energy conversion via hot electron internal photoemission in metallic nanostructures: Efficiency estimates

    SciTech Connect (OSTI)

    Leenheer, Andrew J.; Narang, Prineha; Atwater, Harry A.; Lewis, Nathan S.

    2014-04-07

    Collection of hot electrons generated by the efficient absorption of light in metallic nanostructures, in contact with semiconductor substrates can provide a basis for the construction of solar energy-conversion devices. Herein, we evaluate theoretically the energy-conversion efficiency of systems that rely on internal photoemission processes at metal-semiconductor Schottky-barrier diodes. In this theory, the current-voltage characteristics are given by the internal photoemission yield as well as by the thermionic dark current over a varied-energy barrier height. The Fowler model, in all cases, predicts solar energy-conversion efficiencies of <1% for such systems. However, relaxation of the assumptions regarding constraints on the escape cone and momentum conservation at the interface yields solar energy-conversion efficiencies as high as 1%10%, under some assumed (albeit optimistic) operating conditions. Under these conditions, the energy-conversion efficiency is mainly limited by the thermionic dark current, the distribution of hot electron energies, and hot-electron momentum considerations.

  15. Nearly Perfect Fluidity in a High Temperature Superconductor

    SciTech Connect (OSTI)

    Rameau, J. D.; Reber, T. J.; Yang, H. -B.; Akhanjee, S.; Gu, G. D.; Johnson, P. D.; Campbell, S.

    2014-10-13

    Perfect fluids are characterized as having the smallest ratio of shear viscosity to entropy density, η/s, consistent with quantum uncertainty and causality. So far, nearly perfect fluids have only been observed in the quark-gluon plasma and in unitary atomic Fermi gases, exotic systems that are amongst the hottest and coldest objects in the known universe, respectively. We use angle resolved photoemission spectroscopy to measure the temperature dependence of an electronic analog of η/s in an optimally doped cuprate high-temperature superconductor, finding it too is a nearly perfect fluid around, and above, its superconducting transition temperature Tc.

  16. Nearly Perfect Fluidity in a High Temperature Superconductor

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Rameau, J. D.; Reber, T. J.; Yang, H. -B.; Akhanjee, S.; Gu, G. D.; Johnson, P. D.; Campbell, S.

    2014-10-13

    Perfect fluids are characterized as having the smallest ratio of shear viscosity to entropy density, η/s, consistent with quantum uncertainty and causality. So far, nearly perfect fluids have only been observed in the quark-gluon plasma and in unitary atomic Fermi gases, exotic systems that are amongst the hottest and coldest objects in the known universe, respectively. We use angle resolved photoemission spectroscopy to measure the temperature dependence of an electronic analog of η/s in an optimally doped cuprate high-temperature superconductor, finding it too is a nearly perfect fluid around, and above, its superconducting transition temperature Tc.

  17. High Tc Superconductivity

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    by C. Kim (SSRL), D. H. Lu (Stanford), K. M. Shen (Stanford) and Z.-X. Shen (Stanford/SSRL) Extensive research efforts to study the novel electronic properties of high-Tc superconductors and their related materials by angle-resolved photoemission spectroscopy at a recently commissioned Beam Line 5-4 (led by Z.-X. Shen) continue to be successful, producing many important results. These results, which are highlighted by five articles recently published in Physical Review Letters and one in

  18. Experimental Station 5-4 | Stanford Synchrotron Radiation Lightsource

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    5-4 The BL5-4 station is a normal incidence monochromator beam line optimized for high-resolution angle-resolved photoemission spectroscopy (ARPES) in the photon energy range of 7 - 40 eV. The dedicated experimental end station is equipped with a SCIENTA R4000 electron spectrometer. This system is capable of performing ARPES experiments with a total energy resolution of a few meV and an angular resolution of 0.3°. It is also equipped with a low-temperature sample manipulator with two degree of

  19. Electronic band structure imaging of three layer twisted graphene on single crystal Cu(111)

    SciTech Connect (OSTI)

    Marquez Velasco, J.; Department of Physics, National Technical University of Athens, Athens ; Kelaidis, N.; Xenogiannopoulou, E.; Tsoutsou, D.; Tsipas, P.; Speliotis, Th.; Pilatos, G.; Likodimos, V.; Falaras, P.; Dimoulas, A.; Raptis, Y. S.

    2013-11-18

    Few layer graphene (FLG) is grown on single crystal Cu(111) by Chemical Vapor Deposition, and the electronic valence band structure is imaged by Angle-Resolved Photo-Emission Spectroscopy. It is found that graphene essentially grows polycrystalline. Three nearly ideal Dirac cones are observed along the Cu ?{sup }K{sup } direction in k-space, attributed to the presence of ?4 twisted three layer graphene with negligible interlayer coupling. The number of layers and the stacking order are compatible with Raman data analysis demonstrating the complementarity of the two techniques for a more accurate characterization of FLG.

  20. Unusual Layer-Dependent Charge Distribution, Collective Mode Coupling, and

    Office of Scientific and Technical Information (OSTI)

    Superconductivity in Multilayer Cuprate Ba2Ca3Cu4O8F2 (Journal Article) | SciTech Connect Layer-Dependent Charge Distribution, Collective Mode Coupling, and Superconductivity in Multilayer Cuprate Ba2Ca3Cu4O8F2 Citation Details In-Document Search Title: Unusual Layer-Dependent Charge Distribution, Collective Mode Coupling, and Superconductivity in Multilayer Cuprate Ba2Ca3Cu4O8F2 Low energy ultrahigh momentum resolution angle resolved photoemission spectroscopy study on four-layer self-doped

  1. Unusual layer-dependent charge distribution, collective mode coupling, and

    Office of Scientific and Technical Information (OSTI)

    superconductivity in multilayer cuprate Ba2Ca3Cu4O8F2 (Journal Article) | SciTech Connect layer-dependent charge distribution, collective mode coupling, and superconductivity in multilayer cuprate Ba2Ca3Cu4O8F2 Citation Details In-Document Search Title: Unusual layer-dependent charge distribution, collective mode coupling, and superconductivity in multilayer cuprate Ba2Ca3Cu4O8F2 Low energy ultrahigh momentum resolution angle resolved photoemission spectroscopy study on four-layer self-doped

  2. Real time cumulant approach for charge-transfer satellites in x-ray photoemission spectra

    SciTech Connect (OSTI)

    Kas, Joshua J.; Vila, Fernando D.; Rehr, John J.; Chambers, Scott A.

    2015-03-01

    X-ray photoemission spectra generally exhibit satellite features in addition to quasi-particle peaks due to many-body excitations which have been of considerable theoretical and experimental interest. However, the satellites attributed to charge-transfer (CT) excitations in correlated materials have proved difficult to calculate from first principles. Here we report a real-time, real-space approach for such calculations based on a cumulant representation of the core-hole Green’s function and time-dependent density functional theory. This approach also yields an interpretation of CT satellites in terms of a complex oscillatory, transient response to a suddenly created core hole. Illustrative results for TiO2 and NiO are in good agreement with experiment.

  3. Search for: All records | SciTech Connect

    Office of Scientific and Technical Information (OSTI)

    ... Universal versus Materials-Dependent Two-Gap Behaviour of the High-Tc Cuprate Superconductors: Angle-Resolved Photoemission Study of La2-xSrxCuO4 Yoshida, T. ; Hashimoto, Makoto ; ...

  4. Universal versus Materials-Dependent Two-Gap Behaviour of the...

    Office of Scientific and Technical Information (OSTI)

    Cuprate Superconductors: Angle-Resolved Photoemission Study of La2-xSrxCuO4 We have investigated the doping and temperature dependences of the pseudogap and superconducting gap ...

  5. Hidden Itinerant-Spin Phase in Heavily Overdoped La2-xSrxCuO4...

    Office of Scientific and Technical Information (OSTI)

    Hidden Itinerant-Spin Phase in Heavily Overdoped La2-xSrxCuO4 Superconductors Revealed by Dilute Fe Doping: A Combined Neutron Scattering and Angle-Resolved Photoemission Study...

  6. Raman spectroscopy

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Raman spectroscopy - Sandia Energy Energy Search Icon Sandia Home Locations Contact Us Employee Locator Energy & Climate Secure & Sustainable Energy Future Stationary Power Energy Conversion Efficiency Solar Energy Wind Energy Water Power Supercritical CO2 Geothermal Natural Gas Safety, Security & Resilience of the Energy Infrastructure Energy Storage Nuclear Power & Engineering Grid Modernization Battery Testing Nuclear Fuel Cycle Defense Waste Management Programs Advanced

  7. Two-photon Photoemission of Organic Semiconductor Molecules on Ag(111)

    SciTech Connect (OSTI)

    Yang, Aram; Yang, Aram

    2008-05-15

    Angle- and time-resolved two-photon photoemission (2PPE) was used to study systems of organic semiconductors on Ag(111). The 2PPE studies focused on electronic behavior specific to interfaces and ultrathin films. Electron time dynamics and band dispersions were characterized for ultrathin films of a prototypical n-type planar aromatic hydrocarbon, PTCDA, and representatives from a family of p-type oligothiophenes.In PTCDA, electronic behavior was correlated with film morphology and growth modes. Within a fewmonolayers of the interface, image potential states and a LUMO+1 state were detected. The degree to which the LUMO+1 state exhibited a band mass less than a free electron mass depended on the crystallinity of the layer. Similarly, image potential states were measured to have free electron-like effective masses on ordered surfaces, and the effective masses increased with disorder within the thin film. Electron lifetimes were correlated with film growth modes, such that the lifetimes of electrons excited into systems created by layer-by-layer, amorphous film growth increased by orders of magnitude by only a few monolayers from the surface. Conversely, the decay dynamics of electrons in Stranski-Krastanov systems were limited by interaction with the exposed wetting layer, which limited the barrier to decay back into the metal.Oligothiophenes including monothiophene, quaterthiophene, and sexithiophene were deposited on Ag(111), and their electronic energy levels and effective masses were studied as a function of oligothiophene length. The energy gap between HOMO and LUMO decreased with increasing chain length, but effective mass was found to depend on domains from high- or low-temperature growth conditions rather than chain length. In addition, the geometry of the molecule on the surface, e.g., tilted or planar, substantially affected the electronic structure.

  8. Magnetic circular dichroism in x-ray absorption and core-level photoemission

    SciTech Connect (OSTI)

    Tobin, J.G.; Waddill, G.D.; Gouder, T.H.; Colmenares, C.A.; Pappas, D.P.

    1993-03-17

    Here is reported observation of magnetic circular dichroism in both x-ray absorption and core-level photoemission of ultra thin magnetic films using circularly polarized x-rays. Iron films (1--4 ML) grown on a Cu(001) substrate at 150 K and magnetized perpendicular to the surface show dramatic changes in the L{sub 2,3} branching ratio for different x-ray polarizations. For linearly-polarized x-rays perpendicular to the magnetic axis of the sample the branching ratio was 0.75. For films {ge} 2 ML, this ratio varied from 0.64 to 0.85 for photon spin parallel and anti-parallel, respectively, to the magnetic axis. This effect was observed either by changing the x-ray helicity for a fixed magnetic axis, or by reversing the magnetic axis for a fixed x-ray helicity. Our observation can be analyzed within a simple one-electron picture, if the raw branching ratios are no so that the linear value becomes statistical Furthermore, warming the films to {approximately}300 K eliminated this effect, indicating a loss of magnetization in the film over a temperature range of {approximately}30 K. Finally, reversing the relative orientation of the photon spin and the magnetic axis from parallel to anti-parallel allowed measurement of the exchange splitting of the Fe 2p and 3p core levels which were found to be 0.3 eV and 0.2 eV. respectively. These results are consistent with earlier studies, but the use of off-plane circularly-polarized x-rays from a bending magnet monochromator offers {approximately}2 orders of magnitude greater intensity than typical spin-polarization measurements. Finally, we have performed preliminary x-ray absorption studies of UFe{sub 2}, demonstrating the feasibilty of MCD measurements in 5f as well as 3d materials.

  9. Vacuum space charge effects in sub-picosecond soft X-ray photoemission on a molecular adsorbate layer

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Dell'Angela, M.; Anniyev, T.; Beye, M.; Coffee, R.; Föhlisch, A.; Gladh, J.; Kaya, S.; Katayama, T.; Krupin, O.; Nilsson, A.; et al

    2015-03-01

    Vacuum space charge-induced kinetic energy shifts of O 1s and Ru 3d core levels in femtosecond soft X-ray photoemission spectra (PES) have been studied at a free electron laser (FEL) for an oxygen layer on Ru(0001). We fully reproduced the measurements by simulating the in-vacuum expansion of the photoelectrons and demonstrate the space charge contribution of the high-order harmonics in the FEL beam. Employing the same analysis for 400 nm pump-X-ray probe PES, we can disentangle the delay dependent Ru 3d energy shifts into effects induced by space charge and by lattice heating from the femtosecond pump pulse.

  10. Untangling the contributions of image charge and laser profile for optimal photoemission of high-brightness electron beams

    SciTech Connect (OSTI)

    Portman, J.; Zhang, H.; Makino, K.; Ruan, C. Y.; Berz, M.; Duxbury, P. M.

    2014-11-07

    Using our model for the simulation of photoemission of high brightness electron beams, we investigate the virtual cathode physics and the limits to spatio-temporal and spectroscopic resolution originating from the image charge on the surface and from the profile of the exciting laser pulse. By contrasting the effect of varying surface properties (leading to expanding or pinned image charge), laser profiles (Gaussian, uniform, and elliptical), and aspect ratios (pancake- and cigar-like) under different extraction field strengths and numbers of generated electrons, we quantify the effect of these experimental parameters on macroscopic pulse properties such as emittance, brightness (4D and 6D), coherence length, and energy spread. Based on our results, we outline optimal conditions of pulse generation for ultrafast electron microscope systems that take into account constraints on the number of generated electrons and on the required time resolution.

  11. Metal-Insulator Photocathode Heterojunction for Directed Electron Emission

    SciTech Connect (OSTI)

    Droubay, Timothy C.; Chambers, Scott A.; Joly, Alan G.; Hess, Wayne P.; Nemeth, Karoly; Harkay, Katherine C.; Spentzouris, Linda

    2014-02-14

    New photocathode materials capable of producing intense and directed electron pulses are needed for development of next generation light sources and dynamic transmission electron microscopy. Ideal photocathodes should have high photoemission quantum efficiency (QE) and be capable of delivering collimated and well-shaped pulses of consistent charge under high-field operating conditions. High-brightness and low-intrinsic emittance electron pulses have been predicted for hybrid metal-insulator photocathode designs constructed from three to four monolayer MgO films on atomically flat silver. Here we use angle-resolved photoelectron spectroscopy to confirm directional photoemission and a large increase in QE under ultraviolet laser excitation of an ultrathin MgO film on Ag(001). We observe new low-binding energy photoemission, not seen for Ag(001), and greater electron emission in the normal direction. Under 4.66 eV laser excitation, the photoemission quantum efficiency of the MgO/Ag(001) hybrid photocathode is a factor of seven greater than that for clean Ag(001).

  12. Beamline 10.0.1

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Spectroscopy of Solids Scientific disciplines: Strongly correlated electron systems, magnetism Endstations: High energy resolution spectrometer (HERS) Spin- and angle-resolved...

  13. Exploring the Limits of the Dipole Approximation with Angle-Resolved Electron Time-of-Flight Spectrometry

    SciTech Connect (OSTI)

    Laidman, S.; Pangilinan, J.; Guillemin, R.; Yu, S.U.; Ohrwall, G.; Lindle, D.; Hemmers, O.

    2002-01-01

    Understanding the electronic structure of atoms and molecules is fundamental in determining their basic properties as well as the interactions that occur with different particles such as light. One such interaction is single photoionization; a process in which a photon collides with an atom or molecule and an electron with a certain kinetic energy is emitted, leaving behind a residual ion. Theoretical models of electronic structures use the dipole approximation to simplify x-ray interactions by assuming that the electromagnetic field of the radiation, expressed as a Taylor-series expansion, can be simplified by using only the first term. It has been known for some time that the dipole approximation becomes inaccurate at high photon energies, but the threshold at which this discrepancy begins is ambiguous. In order to enhance our understanding of these limitations, we measured the electron emissions of nitrogen. Beamline 8.0.1 at the Advanced Light Source was used with an electron Time-of-Flight (TOF) end station, which measures the time required for electrons emitted to travel a fixed distance. Data were collected over a broad range of photon energies (413 - 664 eV) using five analyzers rotated to 15 chamber angles. Preliminary analysis indicates that these results confirm the breakdown of the dipole approximation at photon energies well below 1 keV and that this breakdown is greatly enhanced in molecules just above the core-level ionization threshold. As a result, new theoretical models must be made that use higher order terms that were previously truncated.

  14. Heterodyne laser spectroscopy system

    DOE Patents [OSTI]

    Wyeth, Richard W. (Livermore, CA); Paisner, Jeffrey A. (San Ramon, CA); Story, Thomas (Antioch, CA)

    1989-01-01

    A heterodyne laser spectroscopy system utilizes laser heterodyne techniques for purposes of laser isotope separation spectroscopy, vapor diagnostics, processing of precise laser frequency offsets from a reference frequency and the like, and provides spectral analysis of a laser beam.

  15. Heterodyne laser spectroscopy system

    DOE Patents [OSTI]

    Wyeth, Richard W. (Livermore, CA); Paisner, Jeffrey A. (San Ramon, CA); Story, Thomas (Antioch, CA)

    1990-01-01

    A heterodyne laser spectroscopy system utilizes laser heterodyne techniques for purposes of laser isotope separation spectroscopy, vapor diagnostics, processing of precise laser frequency offsets from a reference frequency, and provides spectral analysis of a laser beam.

  16. Momentum-space electronic structures and charge orders of the high-temperature superconductors Ca2-xNaxCuO₂Cl₂ and Bi₂Sr₂CaCu₂O8+δ

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Meng, Jian-Qiao; Brunner, M.; Kim, K.-H.; Lee, H.-G.; Lee, S.-I.; Wen, J. S.; Xu, Z. J.; Gu, G. D.; Gweon, G.-H.

    2011-08-24

    We study the electronic structure of Ca2-xNaxCuO₂Cl₂ and Bi₂Sr₂CaCu₂O8+δ samples in a wide range of doping, using angle-resolved photoemission spectroscopy, with emphasis on the Fermi surface (FS) in the near antinodal region. The “nesting wave vector,” i.e., the wave vector that connects two nearly flat pieces of the FS in the antinodal region, reveals a universal monotonic decrease in magnitude as a function of doping. Comparing our results to the charge order recently observed by scanning tunneling spectroscopy (STS), we conclude that the FS nesting and the charge order pattern seen in STS do not have a direct relationship. Therefore,more »the charge order likely arises due to strong-correlation physics rather than FS nesting physics« less

  17. Momentum-space electronic structures and charge orders of the high-temperature superconductors Ca2-xNaxCuO₂Cl₂ and Bi₂Sr₂CaCu₂O8+δ

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Meng, Jian-Qiao; Brunner, M.; Kim, K.-H.; Lee, H.-G.; Lee, S.-I.; Wen, J. S.; Xu, Z. J.; Gu, G. D.; Gweon, G.-H.

    2011-08-24

    We study the electronic structure of Ca2-xNaxCuO₂Cl₂ and Bi₂Sr₂CaCu₂O8+δ samples in a wide range of doping, using angle-resolved photoemission spectroscopy, with emphasis on the Fermi surface (FS) in the near antinodal region. The “nesting wave vector,” i.e., the wave vector that connects two nearly flat pieces of the FS in the antinodal region, reveals a universal monotonic decrease in magnitude as a function of doping. Comparing our results to the charge order recently observed by scanning tunneling spectroscopy (STS), we conclude that the FS nesting and the charge order pattern seen in STS do not have a direct relationship. Therefore,more » the charge order likely arises due to strong-correlation physics rather than FS nesting physics« less

  18. Sandia Energy - Photoionization Mass Spectroscopy

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Photoionization Mass Spectroscopy Home Transportation Energy Predictive Simulation of Engines Diagnostics Gas-Phase Diagnostics Photoionization Mass Spectroscopy Photoionization...

  19. Near-ambient X-ray photoemission spectroscopy and kinetic approach to the mechanism of carbon monoxide oxidation over lanthanum substituted cobaltites

    SciTech Connect (OSTI)

    Hueso, J. L.; Martinez-Martinez, D.; Cabalerro, Alfonso; Gonzalez-Elipe, Agustin Rodriguez; Mun, Bongjin Simon; Salmeron, Miquel

    2009-07-31

    We have studied the oxidation of carbon monoxide over a lanthanum substituted perovskite (La0.5Sr0.5CoO3-d) catalyst prepared by spray pyrolysis. Under the assumption of a first-order kinetics mechanism for CO, it has been found that the activation energy barrier of the reaction changes from 80 to 40 kJ mol-1 at a threshold temperature of ca. 320 oC. In situ XPS near-ambient pressure ( 0.2 torr) shows that the gas phase oxygen concentration over the sample decreases sharply at ca. 300 oC. These two observations suggest that the oxidation of CO undergoes a change of mechanism at temperatures higher than 300 oC.

  20. Effects of aluminum on epitaxial graphene grown on C-face SiC

    SciTech Connect (OSTI)

    Xia, Chao Johansson, Leif I.; Hultman, Lars; Virojanadara, Chariya; Niu, Yuran

    2015-05-21

    The effects of Al layers deposited on graphene grown on C-face SiC substrates are investigated before and after subsequent annealing using low energy electron diffraction (LEED), photoelectron spectroscopy, and angle resolved photoemission. As-deposited layers appear inert. Annealing at a temperature of about 400?C initiates migration of Al through the graphene into the graphene/SiC interface. Further annealing at temperatures from 500?C to 700?C induces formation of an ordered compound, producing a two domain ?7??7R19 LEED pattern and significant changes in the core level spectra that suggest formation of an Al-Si-C compound. Decomposition of this compound starts after annealing at 800?C, and at 1000?C, Al is no longer possible to detect at the surface. On Si-face graphene, deposited Al layers did not form such an Al-Si-C compound, and Al was still detectable after annealing above 1000?C.

  1. Formation of Gapless Fermi Arcs and Fingerprints of Order in the Pseudogap State of Cuprate Superconductors

    SciTech Connect (OSTI)

    Kondo, Takeshi; Palczewski, Ari; Hamaya, Yoichiro; Takeuchi, Tsunehiro; Wen, J. S.; Xu, Z. J.; Gu, Genda; Kaminski, Adam

    2013-10-08

    We use angle-resolved photoemission spectroscopy and a new quantitative approach based on the partial density of states to study properties of seemingly disconnected portions of the Fermi surface (FS) that are present in the pseudogap state of cuprates called Fermi arcs. We find that the normal state FS collapses very abruptly into Fermi arcs at the pseudogap temperature (T*). Surprisingly, the length of the Fermi arcs remains constant over an extended temperature range between (T*) and Tpair, consistent with the presence of an ordered state below T*. These arcs collapse again at the temperature below which pair formation occurs (Tpair) either to a point or a very short arc, whose length is limited by our experimental resolution. The tips of the arcs span between points defining a set of wave vectors in momentum space, which are the fingerprints of the ordered state that causes the pseudogap.

  2. Formation of Gapless Fermi Arcs and Fingerprints of Order in the Pseudogap State of Cuprate Superconductors

    SciTech Connect (OSTI)

    Kondo, Takeshi; Palczewski, Ari D.; Hamaya, Yoichiro; Takeuchi, Tsunehiro; Wen, J. S.; Gu, Genda; Kaminski, Adam

    2013-10-11

    We use angle-resolved photoemission spectroscopy and a new quantitative approach based on the partial density of states to study properties of seemingly disconnected portions of the Fermi surface (FS) that are present in the pseudogap state of cuprates called Fermi arcs. We find that the normal state FS collapses very abruptly into Fermi arcs at the pseudogap temperature (T?). Surprisingly, the length of the Fermi arcs remains constant over an extended temperature range between T? and Tpair, consistent with the presence of an ordered state below T?. These arcs collapse again at the temperature below which pair formation occurs (Tpair) either to a point or a very short arc, whose length is limited by our experimental resolution. The tips of the arcs span between points defining a set of wave vectors in momentum space, which are the fingerprints of the ordered state that causes the pseudogap.

  3. Momentum dependence of the superconducting gap and in-gap states in MgB2 multiband superconductor

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Mou, Daixiang; Jiang, Rui; Taufour, Valentin; Bud'ko, S. L.; Canfield, P. C.; Kaminski, Adam

    2015-06-29

    We use tunable laser-based angle-resolved photoemission spectroscopy to study the electronic structure of the multiband superconductor MgB2. These results form the baseline for detailed studies of superconductivity in multiband systems. We find that the magnitude of the superconducting gap on both σ bands follows a BCS-like variation with temperature with Δ0 ~ 7meV. Furthermore, the value of the gap is isotropic within experimental uncertainty and in agreement with a pure s-wave pairing symmetry. We observe in-gap states confined to kF of the σ band that occur at some locations of the sample surface. As a result, the energy of thismore » excitation, ~ 3 meV, was found to be somewhat larger than the previously reported gap on π Fermi sheet and therefore we cannot exclude the possibility of interband scattering as its origin.« less

  4. Strong interaction between electrons and collective excitations in the multiband superconductor MgB2

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Mou, Daixiang; Jiang, Rui; Taufour, Valentin; Flint, Rebecca; Bud'ko, S. L.; Canfield, P. C.; Wen, J. S.; Xu, Z. J.; Gu, Genda; Kaminski, Adam

    2015-04-08

    We use a tunable laser angle-resolved photoemission spectroscopy to study the electronic properties of the prototypical multiband BCS superconductor MgB2. Our data reveal a strong renormalization of the dispersion (kink) at ~65meV, which is caused by the coupling of electrons to the E2g phonon mode. In contrast to cuprates, the 65 meV kink in MgB2 does not change significantly across Tc. More interestingly, we observe strong coupling to a second, lower energy collective mode at a binding energy of 10 meV. As a result, this excitation vanishes above Tc and is likely a signature of the elusive Leggett mode.

  5. Single Dirac Cone Topological Surface State and Unusual Thermoelectric Property of Compounds from a New Topological Insulator Family

    SciTech Connect (OSTI)

    Chen, Y

    2011-08-18

    Angle resolved photoemission spectroscopy (ARPES) study on TlBiTe2 and TlBiSe2 from a Thallium-based III-V-VI2 ternary chalcogenides family revealed a single surface Dirac cone at the center of the Brillouin zone for both compounds. For TlBiSe{sub 2}, the large bulk gap ({approx} 200meV) makes it a topological insulator with better mechanical properties than the previous binary 3D topological insualtor family. For TlBiTe{sub 2}, the observed negative bulk gap indicates it as a semi-metal, rather than a narrow gap semi-conductor as conventionally believed; this semi-metality naturally explains its mysteriously small thermoelectric figure of merit comparing to other compounds in the family. Finally, the unique band structures of TlBiTe{sub 2} also suggests it as a candidate for topological superconductors.

  6. Critical parameters of superconducting materials and structures

    SciTech Connect (OSTI)

    Fluss, M.J.; Howell, R.H.; Sterne, P.A.; Dykes, J.W.; Mosley, W.D.; Chaiken, A.; Ralls, K.; Radousky, H.

    1995-02-01

    We report here the completion of a one year project to investigate the synthesis, electronic structure, defect structure, and physical transport properties of high temperature superconducting oxide materials. During the course of this project we produced some of the finest samples of single crystal detwinned YBa{sub 2}Cu{sub 3}O{sub 7}, and stoichiometrically perfect (Ba,K)BiO{sub 3}. We deduced the Fermi surface of YBa{sub 2}Cu{sub 3}O{sub 7}, (La,Sr){sub 2}CuO{sub 4}, and (Ba,K)BiO{sub 3} through the recording of the electron momentum density in these materials as measured by positron annihilation spectroscopy and angle resolved photoemission. We also performed extensive studies on Pr substituted (Y,Pr)Ba{sub 2}Cu{sub 3}O{sub 7} so as to further understand the origin of the electron pairing leading to superconductivity.

  7. Electronic structure reconstruction across the antiferromagnetic transition in TaFe????Te? spin ladder

    SciTech Connect (OSTI)

    Xu, Min; Wang, Li -Min; Peng, Rui; Ge, Qing -Qin; Chen, Fei; Ye, Zi -Rong; Zhang, Yan; Chen, Su -Di; Xia, Miao; Liu, Rong -Hua; Arita, M.; Shimada, K.; Namatame, H.; Taniguchi, M.; Matsunami, M.; Kimura, S.; Shi, Ming; Chen, Xian -Hui; Yin, Wei -Guo; Ku, Wei; Xie, Bin -Ping; Feng, Dong -Lai

    2015-02-01

    With angle-resolved photoemission spectroscopy, we studied the electronic structure of TaFe????Te?, a two-leg spin ladder compound with a novel antiferromagnetic ground state. Quasi-two-dimensional Fermi surface is observed, with sizable inter-ladder hopping. Moreover, instead of observing an energy gap at the Fermi surface in the antiferromagnetic state, we observed the shifts of various bands. Combining these observations with density-functional-theory calculations, we propose that the large scale reconstruction of the electronic structure, caused by the interactions between coexisting itinerant electrons and local moments, is most likely the driving force of the magnetic transition. Thus TaFe????Te? serves as a simpler platform that contains similar ingredients as the parent compounds of iron-based superconductors.

  8. Electronic structure reconstruction across the antiferromagnetic transition in TaFe₁̣₂₃Te₃ spin ladder

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Xu, Min; Wang, Li -Min; Peng, Rui; Ge, Qing -Qin; Chen, Fei; Ye, Zi -Rong; Zhang, Yan; Chen, Su -Di; Xia, Miao; Liu, Rong -Hua; et al

    2015-02-01

    With angle-resolved photoemission spectroscopy, we studied the electronic structure of TaFe₁̣₂₃Te₃, a two-leg spin ladder compound with a novel antiferromagnetic ground state. Quasi-two-dimensional Fermi surface is observed, with sizable inter-ladder hopping. Moreover, instead of observing an energy gap at the Fermi surface in the antiferromagnetic state, we observed the shifts of various bands. Combining these observations with density-functional-theory calculations, we propose that the large scale reconstruction of the electronic structure, caused by the interactions between coexisting itinerant electrons and local moments, is most likely the driving force of the magnetic transition. Thus TaFe₁̣₂₃Te₃ serves as a simpler platform that containsmore » similar ingredients as the parent compounds of iron-based superconductors.« less

  9. Experimental Realization of a Three-Dimensional Topological Insulator, Bi 2Te3

    SciTech Connect (OSTI)

    Siemons, W.

    2010-02-24

    Three-dimensional topological insulators are a new state of quantum matter with a bulk gap and odd number of relativistic Dirac fermions on the surface. By investigating the surface state of Bi{sub 2}Te{sub 3} with angle-resolved photoemission spectroscopy, we demonstrate that the surface state consists of a single nondegenerate Dirac cone. Furthermore, with appropriate hole doping, the Fermi level can be tuned to intersect only the surface states, indicating a full energy gap for the bulk states. Our results establish that Bi{sub 2}Te{sub 3} is a simple model system for the three-dimensional topological insulator with a single Dirac cone on the surface. The large bulk gap of Bi{sub 2}Te{sub 3} also points to promising potential for high-temperature spintronics applications.

  10. Proton Resonance Spectroscopy

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Resonance Spectroscopy in 36Ar William K. Brooks, Jr. Triangle Universities Nuclear Laboratory Department of Physics Duke University 1988 : iii;; - PROTON RESONANCE SPECTROSCOPY IN 36Ar by William K. Brooks, Jr. Departme'nt of Physics Duke University - Date: ~ 1, ~Zg-~ 1 / Approved: \ ~f1A-ea~ E. G. Bilpuch, ~pervisor < Dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the Department of Physics in the Graduate School of Duke University

  11. Synchronization and Characterization of an Ultra-Short Laser for Photoemission and Electron-Beam Diagnostics Studies at a Radio Frequency Photoinjector

    SciTech Connect (OSTI)

    Maxwell, Timothy; Ruan, Jinhao; Piot, Philippe; Lumpkin, Alex; ,

    2012-03-01

    A commercially-available titanium-sapphire laser system has recently been installed at the Fermilab A0 photoinjector laboratory in support of photoemission and electron beam diagnostics studies. The laser system is synchronized to both the 1.3-GHz master oscillator and a 1-Hz signal use to trigger the radiofrequency system and instrumentation acquisition. The synchronization scheme and performance are detailed. Long-term temporal and intensity drifts are identified and actively suppressed to within 1 ps and 1.5%, respectively. Measurement and optimization of the laser's temporal profile are accomplished using frequency-resolved optical gating.

  12. Hard x-ray photoelectron spectroscopy study of Ge{sub 2}Sb{sub 2}Te{sub 5}; as-deposited amorphous, crystalline, and laser-reamorphized

    SciTech Connect (OSTI)

    Richter, Jan H. Tominaga, Junji; Fons, Paul; Kolobov, Alex V.; Ueda, Shigenori; Yoshikawa, Hideki; Yamashita, Yoshiyuki; Ishimaru, Satoshi; Kobayashi, Keisuke

    2014-02-10

    We have investigated the electronic structure of as-deposited, crystalline, and laser-reamorphized Ge{sub 2}Sb{sub 2}Te{sub 5} using high resolution, hard x-ray photoemission spectroscopy. A shift in the Fermi level as well as a broadening of the spectral features in the valence band and the Ge 3d level between the amorphous and crystalline state is observed. Upon amorphization, Ge 3d and Sb 4d spectra show a surprisingly small breaking of resonant bonds and changes in the bonding character as evidenced by the very similar density of states in all cases.

  13. Effect of Cl{sub 2}- and HBr-based inductively coupled plasma etching on InP surface composition analyzed using in situ x-ray photoelectron spectroscopy

    SciTech Connect (OSTI)

    Bouchoule, S.; Vallier, L.; Patriarche, G.; Chevolleau, T.; Cardinaud, C.

    2012-05-15

    A Cl{sub 2}-HBr-O{sub 2}/Ar inductively coupled plasma (ICP) etching process has been adapted for the processing of InP-based heterostructures in a 300-mm diameter CMOS etching tool. Smooth and anisotropic InP etching is obtained at moderate etch rate ({approx}600 nm/min). Ex situ x-ray energy dispersive analysis of the etched sidewalls shows that the etching anisotropy is obtained through a SiO{sub x} passivation mechanism. The stoichiometry of the etched surface is analyzed in situ using angle-resolved x-ray photoelectron spectroscopy. It is observed that Cl{sub 2}-based ICP etching results in a significantly P-rich surface. The phosphorous layer identified on the top surface is estimated to be {approx}1-1.3-nm thick. On the other hand InP etching in HBr/Ar plasma results in a more stoichiometric surface. In contrast to the etched sidewalls, the etched surface is free from oxides with negligible traces of silicon. Exposure to ambient air of the samples submitted to Cl{sub 2}-based chemistry results in the complete oxidation of the P-rich top layer. It is concluded that a post-etch treatment or a pure HBr plasma step may be necessary after Cl{sub 2}-based ICP etching for the recovery of the InP material.

  14. PROTON RESONANCE SPECTROSCOPY

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    as a i i . : lJIiaSJ :ShUiI,,:;II. Iii II; PROTON RESONANCE SPECTROSCOPY IN 29p LAWRENCE H. JAMES Triangle Universities Nuclear Laboratory Department of Physics North Carolina State University 1989 - - .. - .. - .. Abstract James, Lawrence Hoy Proton Resonance Spectroscopy in 29 p (Under the direc- tion of Gary E. Mitchell) Proton elastic scattering on 28Si was measured with good beam energy resolution in the proton energy range Ep=1.4 to E =3.75 MeV, and proton inelastic scattering on p 28Si

  15. SMB, X-ray Absorption Spectroscopy

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Absorption Spectroscopy X-ray Absorption Spectroscopy X-ray absorption spectroscopy (XAS) is a well-established technique for simultaneous local geometric and electronic structure...

  16. energy-dispersive spectroscopy

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    energy-dispersive spectroscopy - Sandia Energy Energy Search Icon Sandia Home Locations Contact Us Employee Locator Energy & Climate Secure & Sustainable Energy Future Stationary Power Energy Conversion Efficiency Solar Energy Wind Energy Water Power Supercritical CO2 Geothermal Natural Gas Safety, Security & Resilience of the Energy Infrastructure Energy Storage Nuclear Power & Engineering Grid Modernization Battery Testing Nuclear Fuel Cycle Defense Waste Management Programs

  17. Nonlinear Laser Spectroscopy

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Laser Spectroscopy - Sandia Energy Energy Search Icon Sandia Home Locations Contact Us Employee Locator Energy & Climate Secure & Sustainable Energy Future Stationary Power Energy Conversion Efficiency Solar Energy Wind Energy Water Power Supercritical CO2 Geothermal Natural Gas Safety, Security & Resilience of the Energy Infrastructure Energy Storage Nuclear Power & Engineering Grid Modernization Battery Testing Nuclear Fuel Cycle Defense Waste Management Programs Advanced

  18. Photoionization Mass Spectroscopy

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Photoionization Mass Spectroscopy - Sandia Energy Energy Search Icon Sandia Home Locations Contact Us Employee Locator Energy & Climate Secure & Sustainable Energy Future Stationary Power Energy Conversion Efficiency Solar Energy Wind Energy Water Power Supercritical CO2 Geothermal Natural Gas Safety, Security & Resilience of the Energy Infrastructure Energy Storage Nuclear Power & Engineering Grid Modernization Battery Testing Nuclear Fuel Cycle Defense Waste Management Programs

  19. Element-specific study of epitaxial NiO/Ag/CoO/Fe films grown on vicinal Ag(001) using photoemission electron microscopy

    SciTech Connect (OSTI)

    Meng, Y.; Li, J.; Tan, A.; Jin, E.; Son, J.; Park, J. S.; Doran, A.; Young, A. T.; Scholl, A.; Arenholz, E.; Wu, J.; Hwang, C.; Zhao, H. W.; Qiu, Z. Q.

    2011-01-10

    NiO/Ag/CoO/Fe single crystalline films are grown epitaxially on a vicinal Ag(001) substrate using molecular beam epitaxy and investigated by photoemission electron microscopy. We find that after zero-field cooling, the in-plane Fe magnetization switches from parallel to perpendicular direction of the atomic steps of the vicinal surface at thinner CoO thickness but remains in its original direction parallel to the steps at thicker CoO thickness. CoO and NiO domain imaging result shows that both CoO/Fe and NiO/CoO spins are perpendicularly coupled, suggesting that the Fe magnetization switching may be associated with the rotatable-frozen spin transition of the CoO film.

  20. Electric field and temperature dependence of dielectric permittivity in strontium titanate investigated by a photoemission study on Pt/SrTiO{sub 3}:Nb junctions

    SciTech Connect (OSTI)

    Hirose, Sakyo; Okushi, Hideyo; Yoshikawa, Hideki; Adachi, Yutaka; Ohsawa, Takeo; Haneda, Hajime; Ueda, Shigenori; Ando, Akira; Ohashi, Naoki

    2015-05-11

    Schottky junctions made from platinum and niobium-doped strontium titanate (SrTiO{sub 3}:Nb) were investigated by hard X-ray photoemission (HXPES) and through a band bending behavior simulation using a phenomenological model, which assumes a decrease in dielectric constant due to an electric field. Thus, we confirmed that the observed HXPES spectra at relatively high temperatures, e.g., >250?K, were well simulated using this phenomenological model. In contrast, it was inferred that the model was not appropriate for junction behavior at lower temperatures, e.g., <150?K. Therefore, a reconstruction of the phenomenological model is necessary to adequately explain the dielectric properties of SrTiO{sub 3}.

  1. PROJECT PROFILE: Correlative Electronic Spectroscopies for Increasing...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    PROJECT PROFILE: Correlative Electronic Spectroscopies for Increasing Photovoltaic Efficiency PROJECT PROFILE: Correlative Electronic Spectroscopies for Increasing Photovoltaic ...

  2. Array-based photoacoustic spectroscopy

    DOE Patents [OSTI]

    Autrey, S. Thomas; Posakony, Gerald J.; Chen, Yu

    2005-03-22

    Methods and apparatus for simultaneous or sequential, rapid analysis of multiple samples by photoacoustic spectroscopy are disclosed. A photoacoustic spectroscopy sample array including a body having at least three recesses or affinity masses connected thereto is used in conjunction with a photoacoustic spectroscopy system. At least one acoustic detector is positioned near the recesses or affinity masses for detection of acoustic waves emitted from species of interest within the recesses or affinity masses.

  3. Resonant ultrasound spectroscopy

    DOE Patents [OSTI]

    Migliori, Albert (Santa Fe, NM)

    1991-01-01

    A resonant ultrasound spectroscopy method provides a unique characterization of an object for use in distinguishing similar objects having physical differences greater than a predetermined tolerance. A resonant response spectrum is obtained for a reference object by placing excitation and detection transducers at any accessible location on the object. The spectrum is analyzed to determine the number of resonant response peaks in a predetermined frequency interval. The distribution of the resonance frequencies is then characterized in a manner effective to form a unique signature of the object. In one characterization, a small frequency interval is defined and stepped though the spectrum frequency range. Subsequent objects are similarly characterized where the characterizations serve as signatures effective to distinguish objects that differ from the reference object by more than the predetermined tolerance.

  4. The light meson spectroscopy program

    SciTech Connect (OSTI)

    Smith, Elton S.

    2014-06-01

    Recent discoveries of a number of unexpected new charmomium-like meson states at the BaBar and Belle B-factories have demonstrated how little is still known about meson spectroscopy. In this talk we will review recent highlights of the light quark spectroscopy from collider and fixed target experiments.

  5. Quantifying electronic correlation strength in a complex oxide: a combined DMFT and ARPES study of LaNiO{sub 3}

    SciTech Connect (OSTI)

    Nowadnick, E. A.; Ruf, J. P.; Park, H.; King, P. D. C.; Schlom, D. G.; Shen, K. M.; Millis, A. J.

    2015-12-07

    The electronic correlation strength is a basic quantity that characterizes the physical properties of materials such as transition metal oxides. Determining correlation strengths requires both precise definitions and a careful comparison between experiment and theory. In this paper, we define the correlation strength via the magnitude of the electron self-energy near the Fermi level. For the case of LaNiO3, we obtain both the experimental and theoretical mass enhancements m/m by considering high resolution angle-resolved photoemission spectroscopy (ARPES) measurements and density functional+dynamical mean field theory (DFT+DMFT) calculations.We use valence-band photoemission data to constrain the free parameters in the theory and demonstrate a quantitative agreement between the experiment and theory when both the realistic crystal structure and strong electronic correlations are taken into account. In addition, by considering DFT+DMFT calculations on epitaxially strained LaNiO3, we find a strain-induced evolution of m/m in qualitative agreement with trends derived from optics experiments. These results provide a benchmark for the accuracy of the DFT+DMFT theoretical approach, and can serve as a test case when considering other complex materials. By establishing the level of accuracy of the theory, this work also will enable better quantitative predictions when engineering new emergent properties in nickelate heterostructures.

  6. Direct spectroscopic evidence for completely filled Cu 3d shell in BaCu₂As₂ and α – BaCu₂Sb₂

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Wu, S. F.; Richard, P.; van Roekeghem, A.; Nie, S. M.; Miao, H.; Xu, N.; Qian, T.; Saparov, B.; Fang, Z.; Biermann, S.; et al

    2015-06-08

    We use angle-resolved photoemission spectroscopy to extract the band dispersion and the Fermi surface of BaCu₂As₂ and α - BaCu₂Sb₂. While the Cu 3d bands in both materials are located around 3.5 eV below the Fermi level, the low-energy photoemission intensity mainly comes from As 4p states, suggesting a completely filled Cu 3d shell. The splitting of the As 3d core levels and the lack of pronounced three-dimensionality in the measured band structure of BaCu₂As₂ indicate a surface state likely induced by the cleavage of this material in the collapsed tetragonal phase, which is consistent with our observation of amore »Cu⁺¹ oxidation state. However, the observation of Cu states at similar energy in α - BaCu₂Sb₂ without the pnictide-pnictide interlayer bonding characteristic of the collapsed tetragonal phase suggests that the short interlayer distance in BaCu₂As₂ follows from the stability of the Cu⁺¹ rather than the other way around. Our results confirm the prediction that BaCu₂As₂ is an sp metal with weak electronic correlations.« less

  7. Probing hot-electron effects in wide area plasmonic surfaces using X-ray photoelectron spectroscopy

    SciTech Connect (OSTI)

    Ayas, Sencer; Cupallari, Andi; Dana, Aykutlu

    2014-12-01

    Plasmon enhanced hot carrier formation in metallic nanostructures increasingly attracts attention due to potential applications in photodetection, photocatalysis, and solar energy conversion. Here, hot-electron effects in nanoscale metal-insulator-metal (MIM) structures are investigated using a non-contact X-ray photoelectron spectroscopy based technique using continuous wave X-ray and laser excitations. The effects are observed through shifts of the binding energy of the top metal layer upon excitation with lasers of 445, 532, and 650?nm wavelength. The shifts are polarization dependent for plasmonic MIM grating structures fabricated by electron beam lithography. Wide area plasmonic MIM surfaces fabricated using a lithography free route by the dewetting of evaporated Ag on HfO{sub 2} exhibit polarization independent optical absorption and surface photovoltage. Using a simple model and making several assumptions about the magnitude of the photoemission current, the responsivity and external quantum efficiency of wide area plasmonic MIM surfaces are estimated as 500?nA/W and 11 10{sup ?6} for 445?nm illumination.

  8. ESC FY2002 Annual Report: Synchrotron-Radiation-Based Photoelectron Spectroscopy at the Advanced Light Source

    SciTech Connect (OSTI)

    Tobin, J G; Chung, B W; Schulze, R K; Shuh, D K

    2002-10-04

    Despite recent intensive experimental effort, the electronic structure of Pu, particularly {delta}-Pu, remains ill defined. An evaluation of our previous synchrotron-radiation-based investigation of {alpha}-Pu and {delta}-Pu has lead to a new paradigm for the interpretation of photoemission spectra of U, Np, {alpha}-Pu, {delta}-Pu and Am. This approach is founded upon a model in which spin and spin-orbit splittings are included in the picture of the 5f states and upon the observation of chiral/spin-dependent effects in non-magnetic systems. By extending a quantitative model developed for the interpretation of core level spectroscopy in magnetic systems, it is possible to predict the contributions of the individual component states within the 5-f manifold. This has lead to a remarkable agreement between the results of the model and the previously collected spectra of U, Np, Pu and Am, particularly {delta}-Pu, and to a prediction of what we might expect to see in future spin-resolving experiments.

  9. Infrared microcalorimetric spectroscopy using quantum cascade...

    Office of Scientific and Technical Information (OSTI)

    Infrared microcalorimetric spectroscopy using quantum cascade lasers Citation Details In-Document Search Title: Infrared microcalorimetric spectroscopy using quantum cascade lasers...

  10. Cavity-Enhanced Transient Absorption Spectroscopy: Ultrafast...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Cavity-Enhanced Transient Absorption Spectroscopy: Ultrafast Spectroscopy goes Ultra-Sensitive Wednesday, November 11, 2015 - 3:00pm SLAC, Redtail Hawk Conference Room 108A...

  11. Ring resonant cavities for spectroscopy

    DOE Patents [OSTI]

    Zare, R.N.; Martin, J.; Paldus, B.A.; Xie, J.

    1999-06-15

    Ring-shaped resonant cavities for spectroscopy allow a reduction in optical feedback to the light source, and provide information on the interaction of both s- and p-polarized light with samples. A laser light source is locked to a single cavity mode. An intracavity acousto-optic modulator may be used to couple light into the cavity. The cavity geometry is particularly useful for Cavity Ring-Down Spectroscopy (CRDS). 6 figs.

  12. Ring resonant cavities for spectroscopy

    DOE Patents [OSTI]

    Zare, Richard N. (Stanford, CA); Martin, Juergen (Jena-Wogau, DE); Paldus, Barbara A. (Stanford, CA); Xie, Jinchun (Sunnyvale, CA)

    1999-01-01

    Ring-shaped resonant cavities for spectroscopy allow a reduction in optical feedback to the light source, and provide information on the interaction of both s- and p-polarized light with samples. A laser light source is locked to a single cavity mode. An intracavity acousto-optic modulator may be used to couple light into the cavity. The cavity geometry is particularly useful for Cavity Ring-Down Spectroscopy (CRDS).

  13. TIME-RESOLVED VIBRATIONAL SPECTROSCOPY

    SciTech Connect (OSTI)

    Andrei Tokmakoff, MIT; Paul Champion, Northeastern University; Edwin J. Heilweil, NIST; Keith A. Nelson, MIT; Larry Ziegler, Boston University

    2009-05-14

    This document contains the Proceedings from the 14th International Conference on Time-Resolved Vibrational Spectroscopy, which was held in Meredith, NH from May 9-14, 2009. The study of molecular dynamics in chemical reaction and biological processes using time-resolved spectroscopy plays an important role in our understanding of energy conversion, storage, and utilization problems. Fundamental studies of chemical reactivity, molecular rearrangements, and charge transport are broadly supported by the DOE’s Office of Science because of their role in the development of alternative energy sources, the understanding of biological energy conversion processes, the efficient utilization of existing energy resources, and the mitigation of reactive intermediates in radiation chemistry. In addition, time-resolved spectroscopy is central to all five of DOE’s grand challenges for fundamental energy science. The Time-Resolved Vibrational Spectroscopy conference is organized biennially to bring the leaders in this field from around the globe together with young scientists to discuss the most recent scientific and technological advances. The latest technology in ultrafast infrared, Raman, and terahertz spectroscopy and the scientific advances that these methods enable were covered. Particular emphasis was placed on new experimental methods used to probe molecular dynamics in liquids, solids, interfaces, nanostructured materials, and biomolecules.

  14. Nitrogen doping of chemical vapor deposition grown graphene on 4H-SiC (0001)

    SciTech Connect (OSTI)

    Urban, J. M.; Binder, J.; Wysmo?ek, A.; D?browski, P.; Strupi?ski, W.; Kopciuszy?ski, M.; Ja?ochowski, M.; Klusek, Z.

    2014-06-21

    We present optical, electrical, and structural properties of nitrogen-doped graphene grown on the Si face of 4H-SiC (0001) by chemical vapor deposition method using propane as the carbon precursor and N{sub 2} as the nitrogen source. The incorporation of nitrogen in the carbon lattice was confirmed by X-ray photoelectron spectroscopy. Angle-resolved photoemission spectroscopy shows carrier behavior characteristic for massless Dirac fermions and confirms the presence of a graphene monolayer in the investigated nitrogen-doped samples. The structural and electronic properties of the material were investigated by Raman spectroscopy. A systematical analysis of the graphene Raman spectra, including D, G, and 2D bands, was performed. In the case of nitrogen-doped samples, an electron concentration on the order of 510 10{sup 12}?cm{sup ?2} was estimated based upon Raman and Hall effect measurements and no clear dependence of the carrier concentration on nitrogen concentration used during growth was observed. This high electron concentration can be interpreted as both due to the presence of nitrogen in graphitic-like positions of the graphene lattice as well as to the interaction with the substrate. A greater intensity of the Raman D band and increased inhomogeneity, as well as decreased electron mobility, observed for nitrogen-doped samples, indicate the formation of defects and a modification of the growth process induced by nitrogen doping.

  15. Superconducting order parameter in nonmagnetic borocarbides RNi₂B₂C (R=Y, Lu) probed by point-contact Andreev reflection spectroscopy

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Lu, X.; Park, W. K.; Yeo, S.; Oh, K.-H.; Lee, S.-I.; Bud’ko, S. L.; Canfield, P. C.; Greene, L. H.

    2011-03-25

    We report on the measurements of the superconducting order parameter in the nonmagnetic borocarbides LuNi₂B₂C and YNi₂B₂C. Andreev conductance spectra are obtained from nanoscale metallic junctions on single crystal surfaces prepared along three major crystallographic orientations: [001], [110], and [100]. The gap values extracted by the single-gap Blonder-Tinkham-Klapwijk model follow the theoretical predictions as a function of temperature and magnetic field and exhibit a small anisotropy with no indication of proposed gap nodes along the [100] and [010] directions. These observations are robust and reproducible among all the measurements on two different sets of LuNi₂B₂C crystals and one set ofmore » YNi₂B₂C crystals. We suggest that the possible gap nodes in the [100] direction may be masked by two effects: different gap anisotropy across multiple Fermi surfaces, as reported in the recent photoemission spectroscopy, and the large tunneling cone. Our results provide a consistent picture of the superconducting gap structure in these materials, addressing the controversy particularly in the reported results of point-contact Andreev reflection spectroscopy.« less

  16. Soft X-Ray and Vacuum Ultraviolet Based Spectroscopy of the Actinides...

    Office of Scientific and Technical Information (OSTI)

    spectroscopy, Synchrotron-radiation-based photoelectron spectroscopy, Soft x-ray absorption spectroscopy, Soft x-ray emission spectroscopy, Inverse photoelectron spectroscopy,...

  17. Spectroscopy

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    correlations in solids, atoms, and ions; and to the study of reaction pathways in chemical dynamics. At the lowest end of this energy range (below 1 eV) we have infrared,...

  18. Twofold enhancement of the hidden-order/large-moment antiferromagnetic phase boundary in the URu2-xFexSi₂ system

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Kanchanavatee, N.; Janoschek, M.; Baumbach, R. E.; Hamlin, J. J.; Zocco, D. A.; Huang, K.; Maple, M. B.

    2011-12-16

    Electrical resistivity, specific heat, and magnetization measurements on URu2-xFexSi₂ reveal a twofold enhancement of the “hidden-order” (HO)/large-moment antiferromagnetic (LMAFM) phase boundary T₀(x). The T₀(Pch) curve, obtained by converting x to “chemical pressure” Pch, is strikingly similar to the T₀(P) curve, where P is applied pressure, for URu₂Si₂ both exhibit a “kink” at 1.5 GPa and a maximum at ~7 GPa. This similarity suggests that the HO-LMAFM transition at 1.5 GPa in URu₂Si₂ occurs at x ≈ 0.2 (Pch≈1.5 GPa) in URu2-xFexSi₂. URu2-xFexSi₂ provides an opportunity for studying the HO and LMAFM phases with methods that probe the electronic structure [e.g.,more » scanning tunneling microscopy (STM), angle-resolved photoemission spectroscopy (ARPES), and point-contact spectroscopy (PCS)] but cannot be used under pressure.« less

  19. Superconductivity Distorted by the Coexisting Pseudogap in the Antinodal

    Office of Scientific and Technical Information (OSTI)

    Region of Bi1.5Pb0.55Sr1.6La0.4CuO6+\delta: A Photon-Energy-Dependent Angle-Resolved Photoemission Study (Journal Article) | SciTech Connect Superconductivity Distorted by the Coexisting Pseudogap in the Antinodal Region of Bi1.5Pb0.55Sr1.6La0.4CuO6+\delta: A Photon-Energy-Dependent Angle-Resolved Photoemission Study Citation Details In-Document Search Title: Superconductivity Distorted by the Coexisting Pseudogap in the Antinodal Region of Bi1.5Pb0.55Sr1.6La0.4CuO6+\delta: A

  20. Simultaneous beta and gamma spectroscopy

    DOE Patents [OSTI]

    Farsoni, Abdollah T. (Corvallis, OR); Hamby, David M. (Corvallis, OR)

    2010-03-23

    A phoswich radiation detector for simultaneous spectroscopy of beta rays and gamma rays includes three scintillators with different decay time characteristics. Two of the three scintillators are used for beta detection and the third scintillator is used for gamma detection. A pulse induced by an interaction of radiation with the detector is digitally analyzed to classify the type of event as beta, gamma, or unknown. A pulse is classified as a beta event if the pulse originated from just the first scintillator alone or from just the first and the second scintillator. A pulse from just the third scintillator is recorded as gamma event. Other pulses are rejected as unknown events.

  1. Development of MEMS photoacoustic spectroscopy

    SciTech Connect (OSTI)

    Robinson, Alex Lockwood; Eichenfield, Matthew S.; Griffin, Benjamin; Harvey, Heidi Alyssa; Nielson, Gregory N.; Okandan, Murat; Langlois, Eric; Resnick, Paul James; Shaw, Michael J.; Young, Ian; Givler, Richard C.; Reinke, Charles M.

    2014-01-01

    After years in the field, many materials suffer degradation, off-gassing, and chemical changes causing build-up of measurable chemical atmospheres. Stand-alone embedded chemical sensors are typically limited in specificity, require electrical lines, and/or calibration drift makes data reliability questionable. Along with size, these "Achilles' heels" have prevented incorporation of gas sensing into sealed, hazardous locations which would highly benefit from in-situ analysis. We report on development of an all-optical, mid-IR, fiber-optic based MEMS Photoacoustic Spectroscopy solution to address these limitations. Concurrent modeling and computational simulation are used to guide hardware design and implementation.

  2. Polaron Coherence Condensation in Layered Colossal Resistive Manganites

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Polaron Coherence Condensation in Layered Colossal Resistive Manganites Print Novel quantum phenomena, such as high-temperature superconductivity (HTSC) and colossal magnetoresistance (CMR), arise in certain materials where the interactions between electrons are very strong, but the mechanism driving their appearance remains a major puzzle. Now, angle-resolved photoemission findings from an international team led by researchers from Stanford University and the ALS provide the first direct

  3. Polaron Coherence Condensation in Layered Colossal Resistive Manganites

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Polaron Coherence Condensation in Layered Colossal Resistive Manganites Print Novel quantum phenomena, such as high-temperature superconductivity (HTSC) and colossal magnetoresistance (CMR), arise in certain materials where the interactions between electrons are very strong, but the mechanism driving their appearance remains a major puzzle. Now, angle-resolved photoemission findings from an international team led by researchers from Stanford University and the ALS provide the first direct

  4. Polaron Coherence Condensation in Layered Colossal Resistive Manganites

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Polaron Coherence Condensation in Layered Colossal Resistive Manganites Print Novel quantum phenomena, such as high-temperature superconductivity (HTSC) and colossal magnetoresistance (CMR), arise in certain materials where the interactions between electrons are very strong, but the mechanism driving their appearance remains a major puzzle. Now, angle-resolved photoemission findings from an international team led by researchers from Stanford University and the ALS provide the first direct

  5. Polaron Coherence Condensation in Layered Colossal Resistive Manganites

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Polaron Coherence Condensation in Layered Colossal Resistive Manganites Print Novel quantum phenomena, such as high-temperature superconductivity (HTSC) and colossal magnetoresistance (CMR), arise in certain materials where the interactions between electrons are very strong, but the mechanism driving their appearance remains a major puzzle. Now, angle-resolved photoemission findings from an international team led by researchers from Stanford University and the ALS provide the first direct

  6. Polaron Coherence Condensation in Layered Colossal Resistive Manganites

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Polaron Coherence Condensation in Layered Colossal Resistive Manganites Polaron Coherence Condensation in Layered Colossal Resistive Manganites Print Wednesday, 30 July 2008 00:00 Novel quantum phenomena, such as high-temperature superconductivity (HTSC) and colossal magnetoresistance (CMR), arise in certain materials where the interactions between electrons are very strong, but the mechanism driving their appearance remains a major puzzle. Now, angle-resolved photoemission findings from an

  7. Polaron Coherence Condensation in Layered Colossal Resistive Manganites

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Polaron Coherence Condensation in Layered Colossal Resistive Manganites Print Novel quantum phenomena, such as high-temperature superconductivity (HTSC) and colossal magnetoresistance (CMR), arise in certain materials where the interactions between electrons are very strong, but the mechanism driving their appearance remains a major puzzle. Now, angle-resolved photoemission findings from an international team led by researchers from Stanford University and the ALS provide the first direct

  8. Extracting the Eliashberg Function

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Extracting the Eliashberg Function Print A multitude of important chemical, physical, and biological phenomena are driven by violations of the Born-Oppenheimer approximation (BOA), which decouples electronic from nuclear motion in quantum calculations of solids. Recent advances in experimental techniques combined with ever-growing theoretical capabilities now hold the promise of presenting an unprecedented picture of these violations. By means of high-resolution angle-resolved photoemission at

  9. Extracting the Eliashberg Function

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Extracting the Eliashberg Function Print A multitude of important chemical, physical, and biological phenomena are driven by violations of the Born-Oppenheimer approximation (BOA), which decouples electronic from nuclear motion in quantum calculations of solids. Recent advances in experimental techniques combined with ever-growing theoretical capabilities now hold the promise of presenting an unprecedented picture of these violations. By means of high-resolution angle-resolved photoemission at

  10. Extracting the Eliashberg Function

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Extracting the Eliashberg Function Print A multitude of important chemical, physical, and biological phenomena are driven by violations of the Born-Oppenheimer approximation (BOA), which decouples electronic from nuclear motion in quantum calculations of solids. Recent advances in experimental techniques combined with ever-growing theoretical capabilities now hold the promise of presenting an unprecedented picture of these violations. By means of high-resolution angle-resolved photoemission at

  11. Extracting the Eliashberg Function

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Extracting the Eliashberg Function Print A multitude of important chemical, physical, and biological phenomena are driven by violations of the Born-Oppenheimer approximation (BOA), which decouples electronic from nuclear motion in quantum calculations of solids. Recent advances in experimental techniques combined with ever-growing theoretical capabilities now hold the promise of presenting an unprecedented picture of these violations. By means of high-resolution angle-resolved photoemission at

  12. Extracting the Eliashberg Function

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Extracting the Eliashberg Function Print A multitude of important chemical, physical, and biological phenomena are driven by violations of the Born-Oppenheimer approximation (BOA), which decouples electronic from nuclear motion in quantum calculations of solids. Recent advances in experimental techniques combined with ever-growing theoretical capabilities now hold the promise of presenting an unprecedented picture of these violations. By means of high-resolution angle-resolved photoemission at

  13. Material and Doping Dependence of the Nodal and Antinodal Dispersion Renormalizations in Single- and Multilayer Cuprates

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Johnston, S.; Lee, W. S.; Chen, Y.; Nowadnick, E. A.; Moritz, B.; Shen, Z.-X.; Devereaux, T. P.

    2010-01-01

    We presenmore » t a review of bosonic renormalization effects on electronic carriers observed from angle-resolved photoemission spectra in the cuprates. Specifically, we discuss the viewpoint that these renormalizations represent coupling of the electrons to the lattice and review how materials dependence, such as the number of Cu O 2 layers, and doping dependence can be understood straightforwardly in terms of several aspects of electron-phonon coupling in layered correlated materials.« less

  14. Spectroscopy of Supercapacitor Electrodes In Operando

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Spectroscopy of Supercapacitor Electrodes In Operando Spectroscopy of Supercapacitor Electrodes In Operando Print Wednesday, 27 May 2015 00:00 Future technology will require energy storage systems that have much larger storage capability, rapid charge/discharge cycling, and improved endurance. Progress in these areas demands a more complete understanding of the processes involved in energy storage, from the atomic scale to the device level. Now, using soft x-ray absorption spectroscopy (XAS)

  15. Laser Induced Spectroscopy - Energy Innovation Portal

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Laser Induced Spectroscopy Idaho National Laboratory Contact INL About This Technology Technology Marketing Summary INL's Laser Induced Spectroscopy technology detects and measures the composition of a material or the molecules in the material. It traces the constituents of the material by using laser induced breakdown spectroscopy and laser induced fluorescence under ambient conditions. The technology measures the decay emission values of the excited absorption state and compares it to decay

  16. Optical sensing based on wavelength modulation spectroscopy

    DOE Patents [OSTI]

    Buckley, Steven G. (Redmond, WA); Gharavi, Mohammadreza (Tehran, IR); Borchers; Marco (Berlin, DE)

    2011-06-28

    Techniques, apparatus and systems for using Wavelength Modulation Spectroscopy measurements to optically monitor gas media such as gases in gas combustion chambers.

  17. Combining Feedback Absorption Spectroscopy, Amplified Resonance...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Feedback Absorption Spectroscopy, Amplified Resonance and Low Pressure Sampling for the Measurement of Nitrogen-Containing Compounds in Automotive Emissions Combining Feedback...

  18. Photoacoustic spectroscopy sample array vessel and photoacoustic spectroscopy method for using the same

    DOE Patents [OSTI]

    Amonette, James E.; Autrey, S. Thomas; Foster-Mills, Nancy S.; Green, David

    2005-03-29

    Methods and apparatus for analysis of multiple samples by photoacoustic spectroscopy are disclosed. Particularly, a photoacoustic spectroscopy sample array vessel including a vessel body having multiple sample cells connected thereto is disclosed. At least one acoustic detector is acoustically coupled with the vessel body. Methods for analyzing the multiple samples in the sample array vessels using photoacoustic spectroscopy are provided.

  19. Photoacoustic spectroscopy sample array vessels and photoacoustic spectroscopy methods for using the same

    DOE Patents [OSTI]

    Amonette, James E.; Autrey, S. Thomas; Foster-Mills, Nancy S.

    2006-02-14

    Methods and apparatus for simultaneous or sequential, rapid analysis of multiple samples by photoacoustic spectroscopy are disclosed. Particularly, a photoacoustic spectroscopy sample array vessel including a vessel body having multiple sample cells connected thereto is disclosed. At least one acoustic detector is acoustically positioned near the sample cells. Methods for analyzing the multiple samples in the sample array vessels using photoacoustic spectroscopy are provided.

  20. Photoacoustic Microcantilevers for Spectroscopy - Energy Innovation Portal

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Photoacoustic Microcantilevers for Spectroscopy Oak Ridge National Laboratory Contact ORNL About This Technology Technology Marketing SummaryORNL researchers invented a unique microcantilever design that can identify the chemical structure of minute sample materials using photoacoustic and photothermal spectroscopy. The design advances current technology, which cannot identify specific chemicals, and furthers the detection of vapors, cells, and tissues. The technology can also characterize

  1. Temperature-induced Lifshitz transition in WTe2

    SciTech Connect (OSTI)

    Wu, Yun; Jo, Na Hyun; Ochi, Masayuki; Huang, Lunan; Mou, Daixiang; Bud’ko, Sergey L.; Canfield, P. C.; Trivedi, Nandini; Arita, Ryotaro; Kaminski, Adam

    2015-10-12

    In this study, we use ultrahigh resolution, tunable, vacuum ultraviolet laser-based, angle-resolved photoemission spectroscopy (ARPES), temperature- and field-dependent resistivity, and thermoelectric power (TEP) measurements to study the electronic properties of WTe2, a compound that manifests exceptionally large, temperature-dependent magnetoresistance. The Fermi surface consists of two pairs of electron and two pairs of hole pockets along the X–Γ–X direction. Using detailed ARPES temperature scans, we find a rare example of a temperature-induced Lifshitz transition at T≃160 K, associated with the complete disappearance of the hole pockets. Our electronic structure calculations show a clear and substantial shift of the chemical potential μ(T) due to the semimetal nature of this material driven by modest changes in temperature. This change of Fermi surface topology is also corroborated by the temperature dependence of the TEP that shows a change of slope at T≈175 K and a breakdown of Kohler’s rule in the 70–140 K range. Our results and the mechanisms driving the Lifshitz transition and transport anomalies are relevant to other systems, such as pnictides, 3D Dirac semimetals, and Weyl semimetals.

  2. Importance of the Fermi-surface topology to the superconducting state of the electron-doped pnictide Ba(Fe1-xCox)?As?

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Liu, Chang; Palczewski, A. D.; Dhaka, R. S.; Kondo, Takeshi; Fernandes, R. M.; Mun, E. D.; Hodovanets, H.; Thaler, A. N.; Schmalian, J.; Budko, S. L.; et al

    2011-07-25

    We used angle-resolved photoemission spectroscopy and thermoelectric power to study the poorly explored, highly overdoped side of the phase diagram of Ba(Fe1-xCox)?As? high-temperature superconductor. Our data demonstrate that several Lifshitz transitionstopological changes of the Fermi surfaceoccur for large x. The central hole barrel changes to ellipsoids that are centered at Z at x~0.11 and subsequently disappear around x~0.2; changes in thermoelectric power occur at similar x values. Tc decreases and goes to zero around x~0.15between the two Lifshitz transitions. Beyond x=0.2 the central pocket becomes electron-like and superconductivity does not exist. Our observations reveal the importance of the underlying Fermiologymorein electron-doped iron arsenides. We speculate that a likely necessary condition for superconductivity in these materials is the presence of the central hole pockets rather than nesting between central and corner pockets.less

  3. Temperature-induced Lifshitz transition in WTe2

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Wu, Yun; Jo, Na Hyun; Ochi, Masayuki; Huang, Lunan; Mou, Daixiang; Bud’ko, Sergey L.; Canfield, P. C.; Trivedi, Nandini; Arita, Ryotaro; Kaminski, Adam

    2015-10-12

    In this study, we use ultrahigh resolution, tunable, vacuum ultraviolet laser-based, angle-resolved photoemission spectroscopy (ARPES), temperature- and field-dependent resistivity, and thermoelectric power (TEP) measurements to study the electronic properties of WTe2, a compound that manifests exceptionally large, temperature-dependent magnetoresistance. The Fermi surface consists of two pairs of electron and two pairs of hole pockets along the X–Γ–X direction. Using detailed ARPES temperature scans, we find a rare example of a temperature-induced Lifshitz transition at T≃160 K, associated with the complete disappearance of the hole pockets. Our electronic structure calculations show a clear and substantial shift of the chemical potential μ(T)more » due to the semimetal nature of this material driven by modest changes in temperature. This change of Fermi surface topology is also corroborated by the temperature dependence of the TEP that shows a change of slope at T≈175 K and a breakdown of Kohler’s rule in the 70–140 K range. Our results and the mechanisms driving the Lifshitz transition and transport anomalies are relevant to other systems, such as pnictides, 3D Dirac semimetals, and Weyl semimetals.« less

  4. Pairing, pseudogap and Fermi arcs in cuprates

    SciTech Connect (OSTI)

    Kaminski, Adam; Kondo, Takeshi; Takeuchi, Tsunehiro; Gu, Genda

    2014-04-29

    We use Angle Resolved Photoemission Spectroscopy (ARPES) to study the relationship between the pseudogap, pairing and Fermi arcs in cuprates. High quality data measured over a wide range of dopings reveals a consistent picture of Fermiology and pairing in these materials. The pseudogap is due to an ordered state that competes with superconductivity rather than preformed pairs. Pairing does occur below Tpair ~ 150K and significantly above Tc, but well below T* and the doping dependence of this temperature scale is distinct from that of the pseudogap. The d-wave gap is present below Tpair, and its interplay with strong scattering creates artificial Fermi arcs for Tc ? T ? Tpair. However, above Tpair, the pseudogap exists only at the antipodal region. This leads to presence of real, gapless Fermi arcs close to the node. The length of these arcs remains constant up to T*, where the full Fermi surface is recovered. As a result, we demonstrate that these findings resolve a number of seemingly contradictory scenarios.

  5. Charge density wave transition in single-layer titanium diselenide

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Chen, P.; Chan, Y. -H.; Fang, X. -Y.; Zhang, Y.; Chou, M. Y.; Mo, S. -K.; Hussain, Z.; Fedorov, A. -V.; Chiang, T. -C.

    2015-11-16

    A single molecular layer of titanium diselenide (TiSe2) is a promising material for advanced electronics beyond graphene--a strong focus of current research. Such molecular layers are at the quantum limit of device miniaturization and can show enhanced electronic effects not realizable in thick films. We show that single-layer TiSe2 exhibits a charge density wave (CDW) transition at critical temperature TC=232±5 K, which is higher than the bulk TC=200±5 K. Angle-resolved photoemission spectroscopy measurements reveal a small absolute bandgap at room temperature, which grows wider with decreasing temperature T below TC in conjunction with the emergence of (2 × 2) ordering.more » The results are rationalized in terms of first-principles calculations, symmetry breaking and phonon entropy effects. The behavior of the Bardeen-Cooper-Schrieffer (BCS) gap implies a mean-field CDW order in the single layer and an anisotropic CDW order in the bulk.« less

  6. Charge density wave transition in single-layer titanium diselenide

    SciTech Connect (OSTI)

    Chen, P.; Chan, Y. -H.; Fang, X. -Y.; Zhang, Y.; Chou, M. Y.; Mo, S. -K.; Hussain, Z.; Fedorov, A. -V.; Chiang, T. -C.

    2015-11-16

    A single molecular layer of titanium diselenide (TiSe2) is a promising material for advanced electronics beyond graphene--a strong focus of current research. Such molecular layers are at the quantum limit of device miniaturization and can show enhanced electronic effects not realizable in thick films. We show that single-layer TiSe2 exhibits a charge density wave (CDW) transition at critical temperature TC=232±5 K, which is higher than the bulk TC=200±5 K. Angle-resolved photoemission spectroscopy measurements reveal a small absolute bandgap at room temperature, which grows wider with decreasing temperature T below TC in conjunction with the emergence of (2 × 2) ordering. The results are rationalized in terms of first-principles calculations, symmetry breaking and phonon entropy effects. The behavior of the Bardeen-Cooper-Schrieffer (BCS) gap implies a mean-field CDW order in the single layer and an anisotropic CDW order in the bulk.

  7. Atomic and electronic structures of single-layer FeSe on SrTiO3(001): The role of oxygen deficiency

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Bang, Junhyeok; Li, Zhi; Sun, Y. Y.; Samanta, Amit; Zhang, Y. Y.; Zhang, Wenhao; Wang, Lili; Chen, X.; Ma, Xucun; Xue, Q.-K.; et al

    2013-06-06

    Using first-principles calculation, we propose an interface structure for single triple-layer FeSe on the SrTiO3(001) surface, a high-Tc superconductor found recently. The key component of this structure is the oxygen deficiency on the top layer of the SrTiO3 substrate, as a result of Se etching used in preparing the high-Tc samples. The O vacancies strongly bind the FeSe triple layer to the substrate giving rise to a (2×1) reconstruction, as observed by scanning tunneling microscopy. The enhanced binding correlates to the significant increase of Tc observed in experiment. The O vacancies also serve as the source of electron doping, whichmore » modifies the Fermi surface of the first FeSe layer by filling the hole pocket near the center of the surface Brillouin zone, as suggested from angle-resolved photoemission spectroscopy measurement.« less

  8. Topological crystalline insulator Pb{sub x}Sn{sub 1-x}Te thin films on SrTiO{sub 3} (001) with tunable Fermi levels

    SciTech Connect (OSTI)

    Guo, Hua; Liu, Jun-Wei; Wang, Zhen-Yu; Wu, Rui; Ji, Shuai-Hua; Duan, Wen-Hui; Chen, Xi Xue, Qi-Kun; Yan, Chen-Hui; Zhang, Zhi-Dong; Wang, Li-Li; He, Ke; Ma, Xu-Cun

    2014-05-01

    In this letter, we report a systematic study of topological crystalline insulator Pb{sub x}Sn{sub 1-x}Te (0 < x < 1) thin films grown by molecular beam epitaxy on SrTiO{sub 3}(001). Two domains of Pb{sub x}Sn{sub 1-x}Te thin films with intersecting angle of ? ? 45 were confirmed by reflection high energy diffraction, scanning tunneling microscopy, and angle-resolved photoemission spectroscopy (ARPES). ARPES study of Pb{sub x}Sn{sub 1-x}Te thin films demonstrated that the Fermi level of PbTe could be tuned by altering the temperature of substrate whereas SnTe cannot. An M-shaped valance band structure was observed only in SnTe but PbTe is in a topological trivial state with a large gap. In addition, co-evaporation of SnTe and PbTe results in an equivalent variation of Pb concentration as well as the Fermi level of Pb{sub x}Sn{sub 1-x}Te thin films.

  9. Pairing, pseudogap and Fermi arcs in cuprates

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Kaminski, Adam; Kondo, Takeshi; Takeuchi, Tsunehiro; Gu, Genda

    2014-04-29

    We use Angle Resolved Photoemission Spectroscopy (ARPES) to study the relationship between the pseudogap, pairing and Fermi arcs in cuprates. High quality data measured over a wide range of dopings reveals a consistent picture of Fermiology and pairing in these materials. The pseudogap is due to an ordered state that competes with superconductivity rather than preformed pairs. Pairing does occur below Tpair ~ 150K and significantly above Tc, but well below T* and the doping dependence of this temperature scale is distinct from that of the pseudogap. The d-wave gap is present below Tpair, and its interplay with strong scatteringmore » creates “artificial” Fermi arcs for Tc ≤ T ≤ Tpair. However, above Tpair, the pseudogap exists only at the antipodal region. This leads to presence of real, gapless Fermi arcs close to the node. The length of these arcs remains constant up to T*, where the full Fermi surface is recovered. As a result, we demonstrate that these findings resolve a number of seemingly contradictory scenarios.« less

  10. Observation of the chiral magnetic effect in ZrTe₅

    SciTech Connect (OSTI)

    Li, Qiang; Kharzeev, Dmitri E.; Zhang, Cheng; Huang, Yuan; Pletikosic, I.; Fedorov, A. V.; Zhong, R. D.; Schneeloch, J. A; Gu, G. D.; Valla, T.

    2015-02-08

    The chiral magnetic effect is the generation of electric current induced by chirality imbalance in the presence of magnetic field. It is a macroscopic manifestation of the quantum anomaly in relativistic field theory of chiral fermions (massless spin 1/2 particles with a definite projection of spin on momentum) – a dramatic phenomenon arising from a collective motion of particles and antiparticles in the Dirac sea. The recent discovery of Dirac semimetals with chiral quasi-particles opens a fascinating possibility to study this phenomenon in condensed matter experiments. Here we report on the first observation of chiral magnetic effect through the measurement of magneto-transport in zirconium pentatelluride, ZrTe₅. Our angle-resolved photoemission spectroscopy experiments show that this material’s electronic structure is consistent with a 3D Dirac semimetal. We observe a large negative magnetoresistance when magnetic field is parallel with the current. The measured quadratic field dependence of the magnetoconductance is a clear indication of the chiral magnetic effect. The observed phenomenon stems from the effective transmutation of Dirac semimetal into a Weyl semimetal induced by the parallel electric and magnetic fields that represent a topologically nontrivial gauge field background.

  11. Interfacial mode coupling as the origin of the enhancement of Tc in FeSe films on SrTiO3

    SciTech Connect (OSTI)

    Lee, J. J.; Schmitt, F. T.; Moore, R. G.; Johnston, S.; Cui, Y. -T.; Li, W.; Yi, M.; Liu, Z. K.; Hashimoto, M.; Zhang, Y.; Lu, D. H.; Devereaux, T. P.; Lee, D. -H.; Shen, Z. -X.; /SIMES, Stanford /SLAC /Stanford U., Geballe Lab.

    2014-11-12

    Films of iron selenide (FeSe) one unit cell thick grown on strontium titanate (SrTiO3 or STO) substrates have recently shown superconducting energy gaps opening at temperatures close to the boiling point of liquid nitrogen (77 K), which is a record for the iron-based superconductors. The gap opening temperature usually sets the superconducting transition temperature Tc, as the gap signals the formation of Cooper pairs, the bound electron states responsible for superconductivity. To understand why Cooper pairs form at such high temperatures, we examine the role of the SrTiO3 substrate. Here we report high-resolution angle-resolved photoemission spectroscopy results that reveal an unexpected characteristic of the single-unit-cell FeSe/SrTiO3 system: shake-off bands suggesting the presence of bosonic modes, most probably oxygen optical phonons in SrTiO3, which couple to the FeSe electrons with only a small momentum transfer. Such interfacial coupling assists superconductivity in most channels, including those mediated by spin fluctuations. Our calculations suggest that this coupling is responsible for raising the superconducting gap opening temperature in single-unit-cell FeSe/SrTiO3.

  12. Latent instabilities in metallic LaNiO₃ films by strain control of Fermi-surface topology

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Yoo, Hyang Keun; Hyun, Seung Ill; Moreschini, Luca; Kim, Hyeong -Do; Chang, Young Jun; Sohn, Chang Hee; Jeong, Da Woon; Sinn, Soobin; Kim, Yong Su; Bostwick, Aaron; et al

    2015-03-04

    Strain control is one of the most promising avenues to search for new emergent phenomena in transition metal-oxide films. Here, we investigate the strain-induced changes of electronic structures in strongly correlated LaNiO₃ (LNO) films, using angle-resolved photoemission spectroscopy and the dynamical mean-field theory. The strongly renormalized eg-orbital bands are systematically rearranged by misfit strain to change its fermiology. As tensile strain increases, the hole pocket centered at the A point elongates along the kz-axis and seems to become open, thus changing Fermi-surface (FS) topology from three- to quasi-two-dimensional. Concomitantly, the FS shape becomes flattened to enhance FS nesting. A FSmore » superstructure withQ₁ = (1/2,1/2,1/2) appears in all LNO films, while a tensile-strained LNO film has an additional Q₂ = (1/4,1/4,1/4) modulation, indicating that some instabilities are present in metallic LNO films. Charge disproportionation and spin-density-wave fluctuations observed in other nickelates might be their most probable origins« less

  13. Atomic and electronic structures of single-layer FeSe on SrTiO3(001): The role of oxygen deficiency

    SciTech Connect (OSTI)

    Bang, Junhyeok; Li, Zhi; Sun, Y. Y.; Samanta, Amit; Zhang, Y. Y.; Zhang, Wenhao; Wang, Lili; Chen, X.; Ma, Xucun; Xue, Q.-K.; Zhang, S. B.

    2013-06-06

    Using first-principles calculation, we propose an interface structure for single triple-layer FeSe on the SrTiO3(001) surface, a high-Tc superconductor found recently. The key component of this structure is the oxygen deficiency on the top layer of the SrTiO3 substrate, as a result of Se etching used in preparing the high-Tc samples. The O vacancies strongly bind the FeSe triple layer to the substrate giving rise to a (21) reconstruction, as observed by scanning tunneling microscopy. The enhanced binding correlates to the significant increase of Tc observed in experiment. The O vacancies also serve as the source of electron doping, which modifies the Fermi surface of the first FeSe layer by filling the hole pocket near the center of the surface Brillouin zone, as suggested from angle-resolved photoemission spectroscopy measurement.

  14. Particle-Hole Symmetry Breaking in the Pseudogap State of Bi2201

    SciTech Connect (OSTI)

    Hashimoto, M.; He, R.-H.; Tanaka, K.; Testaud, J.P.; Meevasana1, W.; Moore, R.G.; Lu, D.H.; Yao, H.; Yoshida, Y.; Eisaki, H.; Devereaux, T.P.; Hussain, Z.; Shen, Z.-X.; /SIMES, Stanford /Stanford U., Geballe Lab.

    2011-08-19

    In conventional superconductors, a gap exists in the energy absorption spectrum only below the transition temperature (T{sub c}), corresponding to the energy price to pay for breaking a Cooper pair of electrons. In high-T{sub c} cuprate superconductors above T{sub c}, an energy gap called the pseudogap exists, and is controversially attributed either to pre-formed superconducting pairs, which would exhibit particle-hole symmetry, or to competing phases which would typically break it. Scanning tunnelling microscopy (STM) studies suggest that the pseudogap stems from lattice translational symmetry breaking and is associated with a different characteristic spectrum for adding or removing electrons (particle-hole asymmetry). However, no signature of either spatial or energy symmetry breaking of the pseudogap has previously been observed by angle-resolved photoemission spectroscopy (ARPES). Here we report ARPES data from Bi2201 which reveals both particle-hole symmetry breaking and dramatic spectral broadening indicative of spatial symmetry breaking without long range order, upon crossing through T* into the pseudogap state. This symmetry breaking is found in the dominant region of the momentum space for the pseudogap, around the so-called anti-node near the Brillouin zone boundary. Our finding supports the STM conclusion that the pseudogap state is a broken-symmetry state that is distinct from homogeneous superconductivity.

  15. Persistent order due to transiently enhanced nesting in an electronically excited charge density wave

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Rettig, L.; Cortés, R.; Chu, J. -H.; Fisher, I. R.; Schmitt, F.; Moore, R. G.; Shen, Z. -X.; Kirchmann, P. S.; Wolf, M.; Bovensiepen, U.

    2016-01-25

    Non-equilibrium conditions may lead to novel properties of materials with broken symmetry ground states not accessible in equilibrium as vividly demonstrated by non-linearly driven mid-infrared active phonon excitation. Potential energy surfaces of electronically excited states also allow to direct nuclear motion, but relaxation of the excess energy typically excites fluctuations leading to a reduced or even vanishing order parameter as characterized by an electronic energy gap. Here, using femtosecond time-and angle-resolved photoemission spectroscopy, we demonstrate a tendency towards transient stabilization of a charge density wave after near-infrared excitation, counteracting the suppression of order in the non-equilibrium state. Analysis of themore » dynamic electronic structure reveals a remaining energy gap in a highly excited transient state. In conclusion, our observation can be explained by a competition between fluctuations in the electronically excited state, which tend to reduce order, and transiently enhanced Fermi surface nesting stabilizing the order.« less

  16. Observation of universal strong orbital-dependent correlation effects in iron chalcogenides

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Yi, M.; Liu, Z. -K.; Zhang, Y.; Yu, R.; Zhu, J. -X.; Lee, J. J.; Moore, R. G.; Schmitt, F. T.; Li, W.; Riggs, S. C.; et al

    2015-07-23

    Establishing the appropriate theoretical framework for unconventional superconductivity in the iron-based materials requires correct understanding of both the electron correlation strength and the role of Fermi surfaces. This fundamental issue becomes especially relevant with the discovery of the iron chalcogenide superconductors. Here, we use angle-resolved photoemission spectroscopy to measure three representative iron chalcogenides, FeTe0.56Se0.44, monolayer FeSe grown on SrTiO3 and K0.76Fe1.72Se2. We show that these superconductors are all strongly correlated, with an orbital-selective strong renormalization in the dxy bands despite having drastically different Fermi surface topologies. Furthermore, raising temperature brings all three compounds from a metallic state to a phasemore » where the dxy orbital loses all spectral weight while other orbitals remain itinerant. As a result, these observations establish that iron chalcogenides display universal orbital-selective strong correlations that are insensitive to the Fermi surface topology, and are close to an orbital-selective Mott phase, hence placing strong constraints for theoretical understanding of iron-based superconductors.« less

  17. Many-body ab-initio diffusion quantum Monte Carlo applied to the strongly correlated oxide NiO

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Mitra, Chandrima; Krogel, Jaron T.; Santana, Juan A.; Reboredo, Fernando A.

    2015-10-28

    We present a many-body diffusion quantum Monte Carlo (DMC) study of the bulk and defect properties of NiO. We find excellent agreement with experimental values, within 0.3%, 0.6%, and 3.5% for the lattice constant, cohesive energy, and bulk modulus, respectively. The quasiparticle bandgap was also computed, and the DMC result of 4.72 (0.17) eV compares well with the experimental value of 4.3 eV. Furthermore, DMC calculations of excited states at the L, Z, and the gamma point of the Brillouin zone reveal a flat upper valence band for NiO, in good agreement with Angle Resolved Photoemission Spectroscopy results. To studymoredefect properties, we evaluated the formation energies of the neutral and charged vacancies of oxygen and nickel in NiO. A formation energy of 7.2 (0.15) eV was found for the oxygen vacancy under oxygen rich conditions. For the Ni vacancy, we obtained a formation energy of 3.2 (0.15) eV under Ni rich conditions. These results confirm that NiO occurs as a p-type material with the dominant intrinsic vacancy defect being Ni vacancy.less

  18. Observation of the chiral magnetic effect in ZrTe₅

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Li, Qiang; Kharzeev, Dmitri E.; Zhang, Cheng; Huang, Yuan; Pletikosic, I.; Fedorov, A. V.; Zhong, R. D.; Schneeloch, J. A; Gu, G. D.; Valla, T.

    2015-02-08

    The chiral magnetic effect is the generation of electric current induced by chirality imbalance in the presence of magnetic field. It is a macroscopic manifestation of the quantum anomaly in relativistic field theory of chiral fermions (massless spin 1/2 particles with a definite projection of spin on momentum) – a dramatic phenomenon arising from a collective motion of particles and antiparticles in the Dirac sea. The recent discovery of Dirac semimetals with chiral quasi-particles opens a fascinating possibility to study this phenomenon in condensed matter experiments. Here we report on the first observation of chiral magnetic effect through the measurementmore » of magneto-transport in zirconium pentatelluride, ZrTe₅. Our angle-resolved photoemission spectroscopy experiments show that this material’s electronic structure is consistent with a 3D Dirac semimetal. We observe a large negative magnetoresistance when magnetic field is parallel with the current. The measured quadratic field dependence of the magnetoconductance is a clear indication of the chiral magnetic effect. The observed phenomenon stems from the effective transmutation of Dirac semimetal into a Weyl semimetal induced by the parallel electric and magnetic fields that represent a topologically nontrivial gauge field background.« less

  19. Accelerating the development of transparent graphene electrodes...

    Office of Scientific and Technical Information (OSTI)

    phenyl-modified graphene were studied by photoemission spectroscopy, spatially resolved Raman spectroscopy, and water contact angle measurement. Covalent attachment rehybridized...

  20. Electronic structure of the heavy-fermion caged compound Ce?Pd??X? (X = Si, Ge) studied by density functional theory and photoelectron spectroscopy

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Yamaoka, Hitoshi; Jarrige, Ignace; Schwier, Eike F.; Arita, Masashi; Shimada, Kenya; Tsujii, Naohito; Jiang, Jian; Hayashi, Hirokazu; Iwasawa, Hideaki; Namatame, Hirofumi; et al

    2015-03-30

    The electronic structure of Ce?Pd??X? (X = Si, Ge) has been studied using detailed density functional theory (DFT) calculations and high-resolution photoelectron spectroscopy (PES) measurements. The orbital decomposition of the electronic structure by DFT calculations indicates that Ce atoms at the (8c) site surrounded by 16 Pd atoms have a more localized nature and a tendency to be magnetic. Ce atoms in the (4a) site surrounded by 12 Pd and 6 X atoms, on the other, show only a negligible magnetic moment. In the photoemission valence-band spectra we observe a strong f? (Ce??) component with a small fraction of fmore(Ce?) component. The spectral weight of f component near the Fermi level Ce?Pd??Si? is stronger than that for Ce?Pd??Ge? at the 4d-4f resonance, suggesting stronger c-f hybridization in the former. This may hint to the origin of the large electronic specific coefficient of Ce?Pd??Si? compared to Ce?Pd??Ge?.less

  1. Electronic structure of the heavy-fermion caged compound Ce3Pd20X6(X=Si,Ge) studied by density functional theory and photoelectron spectroscopy

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Yamaoka, Hitoshi; Schwier, Eike F.; Arita, Masashi; Shimada, Kenya; Tsujii, Naohito; Jarrige, Ignace; Jiang, Jian; Hayashi, Hirokazu; Iwasawa, Hideaki; Namatame, Hirofumi; et al

    2015-03-30

    The electronic structure of Ce₃Pd₂₀X₆ (X = Si, Ge) has been studied using detailed density functional theory (DFT) calculations and high-resolution photoelectron spectroscopy (PES) measurements. The orbital decomposition of the electronic structure by DFT calculations indicates that Ce atoms at the (8c) site surrounded by 16 Pd atoms have a more localized nature and a tendency to be magnetic. Ce atoms in the (4a) site surrounded by 12 Pd and 6 X atoms, on the other, show only a negligible magnetic moment. In the photoemission valence-band spectra we observe a strong f⁰ (Ce⁴⁺) component with a small fraction of f¹more »(Ce³⁺) component. The spectral weight of f¹ component near the Fermi level Ce₃Pd₂₀Si₆ is stronger than that for Ce₃Pd₂₀Ge₆ at the 4d-4f resonance, suggesting stronger c-f hybridization in the former. This may hint to the origin of the large electronic specific coefficient of Ce₃Pd₂₀Si₆ compared to Ce₃Pd₂₀Ge₆.« less

  2. Raman spectroscopy in hot compressed hydrogen and nitrogen -...

    Office of Scientific and Technical Information (OSTI)

    Raman spectroscopy in hot compressed hydrogen and nitrogen - implications for the intramolecular potential Citation Details In-Document Search Title: Raman spectroscopy in hot...

  3. Impedance spectroscopy of organic magnetoresistance devices-Effect...

    Office of Scientific and Technical Information (OSTI)

    Impedance spectroscopy of organic magnetoresistance devices-Effect of interface disorder Citation Details In-Document Search Title: Impedance spectroscopy of organic ...

  4. First Principles Calculations and NMR Spectroscopy of Electrode...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    and NMR Spectroscopy of Electrode Materials First Principles Calculations and NMR Spectroscopy of Electrode Materials 2011 DOE Hydrogen and Fuel Cells Program, and Vehicle...

  5. Operando Raman and Theoretical Vibration Spectroscopy of Non...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Operando Raman and Theoretical Vibration Spectroscopy of Non-PGM Catalysts Operando Raman and Theoretical Vibration Spectroscopy of Non-PGM Catalysts Presentation about...

  6. Updated Spitzer emission spectroscopy of bright transiting hot...

    Office of Scientific and Technical Information (OSTI)

    Updated Spitzer emission spectroscopy of bright transiting hot Jupiter HD 189733b Citation Details In-Document Search Title: Updated Spitzer emission spectroscopy of bright...

  7. First Principles Calculations (and NMR Spectroscopy of Electrode...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    (and NMR Spectroscopy of Electrode Materials) First Principles Calculations (and NMR Spectroscopy of Electrode Materials) 2009 DOE Hydrogen Program and Vehicle Technologies Program...

  8. An internal report: Electron Spectroscopy of the Oxidation and...

    Office of Scientific and Technical Information (OSTI)

    An internal report: Electron Spectroscopy of the Oxidation and Aging of U and Pu Citation Details In-Document Search Title: An internal report: Electron Spectroscopy of the...

  9. Vibrational spectroscopy of water interfaces

    SciTech Connect (OSTI)

    Du, Q.

    1994-12-01

    The second order nonlinear optical processes of second harmonic generation and sum frequency generation are powerful and versatile tools for studying all kinds of surfaces. They possess unusual surface sensitivity due to the symmetry properties of the second order nonlinear susceptibility. The technique of infrared-visible sum frequency generation (SFG) is particularly attractive because it offers a viable way to do vibrational spectroscopy on any surfaces accessible to light with submonolayer sensitivity. In this thesis, the author applies SFG to study a number of important water interfaces. At the air/water interface, hydrophobic solid/water and liquid/water interfaces, it was found that approximately 25% of surface water molecules have one of their hydrogen pointing away from the liquid water. The large number of unsatisfied hydrogen bonds contributes significantly to the large interfacial energy of the hydrophobic surfaces. At the hydrophilic fused quartz/water interface and a fatty acid monolayer covered water surface, the structure and orientation of surface water molecules are controlled by the hydrogen bonding of water molecules with the surface OH groups and the electrostatic interaction with the surface field from the ionization of surface groups. A change of pH value in the bulk water can significantly change the relative importance of the two interactions and cause a drastic change in orientation of the surface water molecules. SFG has also been applied to study the tribological response of some model lubricant films. Monolayers of Langmuir-Blodgett films were found to disorder orientationaly under mildly high pressure and recover promptly upon removal of the applied pressure.

  10. Ultrafast Spectroscopy of Warm Dense Matter

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Spectroscopy of Warm Dense Matter Print Being neither solid, liquid, gas, nor plasma, warm dense matter (WDM) occupies a no man's land in the map of material phases. Its...

  11. Ultrafast Spectroscopy of Warm Dense Matter

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Ultrafast Spectroscopy of Warm Dense Matter Print Being neither solid, liquid, gas, nor plasma, warm dense matter (WDM) occupies a no man's land in the map of material phases. Its...

  12. Research in Neutron Velocity Spectroscopy. Final Report

    DOE R&D Accomplishments [OSTI]

    Rainwater, J.

    1976-10-13

    A brief summary of papers published since the last progress report (June 1974) is presented. The research represents contributions to neutron resonance spectroscopy below 100 keV. (SDF)

  13. Spectroscopy of Supercapacitor Electrodes In Operando

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Spectroscopy of Supercapacitor Electrodes In Operando Print Future technology will require energy storage systems that have much larger storage capability, rapid charge/discharge cycling, and improved endurance. Progress in these areas demands a more complete understanding of the processes involved in energy storage, from the atomic scale to the device level. Now, using soft x-ray absorption spectroscopy (XAS) under operating conditions ("in operando"), researchers have found that the

  14. Spectroscopy of Supercapacitor Electrodes In Operando

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Spectroscopy of Supercapacitor Electrodes In Operando Print Future technology will require energy storage systems that have much larger storage capability, rapid charge/discharge cycling, and improved endurance. Progress in these areas demands a more complete understanding of the processes involved in energy storage, from the atomic scale to the device level. Now, using soft x-ray absorption spectroscopy (XAS) under operating conditions ("in operando"), researchers have found that the

  15. Spectroscopy of Supercapacitor Electrodes In Operando

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Spectroscopy of Supercapacitor Electrodes In Operando Print Future technology will require energy storage systems that have much larger storage capability, rapid charge/discharge cycling, and improved endurance. Progress in these areas demands a more complete understanding of the processes involved in energy storage, from the atomic scale to the device level. Now, using soft x-ray absorption spectroscopy (XAS) under operating conditions ("in operando"), researchers have found that the

  16. Spectroscopy of Supercapacitor Electrodes In Operando

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Spectroscopy of Supercapacitor Electrodes In Operando Print Future technology will require energy storage systems that have much larger storage capability, rapid charge/discharge cycling, and improved endurance. Progress in these areas demands a more complete understanding of the processes involved in energy storage, from the atomic scale to the device level. Now, using soft x-ray absorption spectroscopy (XAS) under operating conditions ("in operando"), researchers have found that the

  17. Spectroscopy of Supercapacitor Electrodes In Operando

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Spectroscopy of Supercapacitor Electrodes In Operando Print Future technology will require energy storage systems that have much larger storage capability, rapid charge/discharge cycling, and improved endurance. Progress in these areas demands a more complete understanding of the processes involved in energy storage, from the atomic scale to the device level. Now, using soft x-ray absorption spectroscopy (XAS) under operating conditions ("in operando"), researchers have found that the

  18. Spectroscopy of Supercapacitor Electrodes In Operando

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Spectroscopy of Supercapacitor Electrodes In Operando Print Future technology will require energy storage systems that have much larger storage capability, rapid charge/discharge cycling, and improved endurance. Progress in these areas demands a more complete understanding of the processes involved in energy storage, from the atomic scale to the device level. Now, using soft x-ray absorption spectroscopy (XAS) under operating conditions ("in operando"), researchers have found that the

  19. PROJECT PROFILE: Correlative Electronic Spectroscopies for Increasing

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Photovoltaic Efficiency | Department of Energy PROJECT PROFILE: Correlative Electronic Spectroscopies for Increasing Photovoltaic Efficiency PROJECT PROFILE: Correlative Electronic Spectroscopies for Increasing Photovoltaic Efficiency Funding Opportunity: SuNLaMP SunShot Subprogram: Photovoltaics Location: National Renewable Energy Laboratory, Golden, CO Amount Awarded: $2,000,000 Recombination limits open-circuit voltages in thin film photovoltaic (PV) devices to 60-65% of the thermodynamic

  20. Ultrafast Spectroscopy of Warm Dense Matter

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Ultrafast Spectroscopy of Warm Dense Matter Ultrafast Spectroscopy of Warm Dense Matter Print Wednesday, 25 April 2012 00:00 Being neither solid, liquid, gas, nor plasma, warm dense matter (WDM) occupies a no man's land in the map of material phases. Its temperature can range between that of planetary cores (tens of thousands K) to that of stellar cores (hundreds of thousands K). Not only is it prevalent throughout the universe, it is relevant to inertial confinement fusion (ICF) and material

  1. Differential Electrochemical Mass Spectroscopy (DEMS) > Analytical

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Resources > Research > The Energy Materials Center at Cornell Analytical Resources In This Section Differential Electrochemical Mass Spectroscopy (DEMS) Electron Microscopy X-Ray Diffraction Differential Electrochemical Mass Spectroscopy (DEMS) DEMS and in situ FTIR Direct alcohol fuel cells are those which utilize small organic molecules, such as methanol or ethanol, as fuels without first reforming them to hydrogen gas. These devices promise to be an efficient means of converting

  2. A Brief History of Spectroscopy on EBIT

    SciTech Connect (OSTI)

    Beiersdorfer, P

    2007-02-28

    In the autumn of 1986, the first electron beam ion trap, EBIT, was put into service as a light source for the spectroscopy of highly charged ions. On the occasion of the twentieth anniversary of EBIT, we review its early uses for spectroscopy, from the first measurements of x rays from L-shell xenon ions in 1986 to its conversion to SuperEBIT in 1992 and rebirth as EBIT-I in 2001. Together with their sibling, EBIT-II, these machines have been used at Livermore to perform a multitude of seminal studies of the physics of highly charged ions.

  3. Laser spectroscopy and dynamics of transient species

    SciTech Connect (OSTI)

    Clouthier, D.J.

    1993-12-01

    The goal of this program is to study the vibrational and electronic spectra and excited state dynamics of a number of transient sulfur and oxygen species. A variety of supersonic jet techniques, as well as high resolution FT-IR and intracavity dye laser spectroscopy, have been applied to these studies.

  4. Noise spectroscopy of an optical microresonator

    SciTech Connect (OSTI)

    Kozlov, G. G.

    2013-05-15

    The noise spectrum is calculated for the intensity of light transmitted through an optical microresonator whose thickness experiences thermal oscillations. The noise spectrum reveals a maximum at the frequency of an acoustic mode localized in the optical microresonator and depends on the size of the illuminated region. The noise intensity estimates show that it can be detected by the modern noise spectroscopy technique.

  5. Nanoparticles and nanowires: synchrotron spectroscopy studies

    SciTech Connect (OSTI)

    Sham, T.K.

    2008-08-11

    This paper reviews the research in nanomaterials conducted in our laboratory in the last decade using conventional and synchrotron radiation techniques. While preparative and conventional characterisation techniques are described, emphasis is placed on the analysis of nanomaterials using synchrotron radiation. Materials of primary interests are metal nanoparticles and semiconductor nanowires and nanoribbons. Synchrotron techniques based on absorption spectroscopy such as X-ray absorption fine structures (XAFS), which includes X-ray absorption near edge structures (XANES) and extended X-ray absorption fine structures (EXFAS), and de-excitation spectroscopy, including X-ray excited optical luminescence (XEOL), time-resolved X-ray excited optical luminescence (TRXEOL) and X-ray emission spectroscopy (XES) are described. We show that the tunability, brightness, polarisation and time structure of synchrotron radiation are providing unprecedented capabilities for nanomaterials analysis. Synchrotron studies of prototype systems such as gold nanoparticles, 1-D nanowires of group IV materials, C, Si and Ge as well as nanodiamond, and compound semiconductors, ZnS, CdS, ZnO and related materials are used to illustrate the power and unique capabilities of synchrotron spectroscopy in the characterisation of local structure, electronic structure and optical properties of nanomaterials.

  6. Spectroscopy and decays of charm and bottom

    SciTech Connect (OSTI)

    Butler, J.N.

    1997-10-01

    After a brief review of the quark model, we discuss our present knowledge of the spectroscopy of charm and bottom mesons and baryons. We go on to review the lifetimes, semileptonic, and purely leptonic decays of these particles. We conclude with a brief discussion B and D mixing and rare decays.

  7. Radiative Bottomonium Spectroscopy at the Y(2, 3S) Resonances...

    Office of Scientific and Technical Information (OSTI)

    Radiative Bottomonium Spectroscopy at the Y(2, 3S) Resonances at BaBar Citation Details In-Document Search Title: Radiative Bottomonium Spectroscopy at the Y(2, 3S) Resonances at...

  8. X-Ray Photoelectron Spectroscopy (XPS) Applied to Soot & What...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Photoelectron Spectroscopy (XPS) Applied to Soot & What It Can Do for You X-Ray Photoelectron Spectroscopy (XPS) Applied to Soot & What It Can Do for You Presentation given at DEER...

  9. A first site of galaxy cluster formation: complete spectroscopy...

    Office of Scientific and Technical Information (OSTI)

    ... Subject: 79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; DUSTS; EVOLUTION; GALAXIES; GALAXY CLUSTERS; LUMINOSITY; MASS; NONLUMINOUS MATTER; RED SHIFT; SIMULATION; SPECTROSCOPY; UNIVERSE ...

  10. Trace Explosive Detection using Photothermal Deflection Spectroscopy

    SciTech Connect (OSTI)

    Krause, Adam R; Van Neste, Charles W; Senesac, Larry R; Thundat, Thomas George; Finot, Eric

    2008-01-01

    Satisfying the conditions of high sensitivity and high selectivity using portable sensors that are also reversible is a challenge. Miniature sensors such as microcantilevers offer high sensitivity but suffer from poor selectivity due to the lack of sufficiently selective receptors. Although many of the mass deployable spectroscopic techniques provide high selectivity, they do not have high sensitivity. Here, we show that this challenge can be overcome by combining photothermal spectroscopy on a bimaterial microcantilever with the mass induced change in the cantilever's resonance frequency. Detection using adsorption-induced resonant frequency shift together with photothermal deflection spectroscopy shows extremely high selectivity with a subnanogram limit of detection for vapor phase adsorbed explosives, such as pentaerythritol tetranitrate (PETN), cyclotrimethylene trinitramine (RDX), and trinitrotoluene (TNT).

  11. (Resonance ionization spectroscopy and its applications)

    SciTech Connect (OSTI)

    Ramsey, J.M.

    1990-10-11

    The Fifth International Symposium in Resonance Ionization Spectroscopy and Its Applications was attended. The Joint Research Centre of the European Communities at Ispra, Italy was also visited. The traveler presented an invited talk, chaired a meeting session and gave an impromptu presentation on how current laser technology limits the development of commercial instrumentation based upon Resonance Ionization Spectroscopy. The conference was truely international with scientists from 19 countries and less than 1/4 from the US. The meeting also provided a health mixture of experimentalists and theoreticians. Technical developments reported included the use of electric field ionization from laser prepared Rydberg states as a way to reduce background signals and commercial development of an optical parametric oscillator for replacing pulsed dye laser. A speaker from the Soviet Union suggested their willingness to market hardware they have developed based upon the resonance ionization technique.

  12. Meson Spectroscopy At Jlab At 12 Gev

    SciTech Connect (OSTI)

    Fegan, Stuart

    2014-12-01

    The 12 GeV upgrade to the Continuous Electron Beam Accelerator Facility (CEBAF) at Jefferson Lab will enable a new generation of experiments in hadronic nuclear physics, seeking to address fundamental questions in our understanding of QCD. The existence of exotic states, suggested by both quark models and lattice calculations, would allow gluonic degrees of freedom to be explored, and may help explain the role played by gluons in the QCD interaction. This article will review the meson spectroscopy program being planned at the lab following the 12 GeV upgrade, utilising real and quasi-real photon beams in two of the lab's four experimental halls, whose distinct capabilities will enable an extensive set of spectroscopy experiments to be performed at the same facility.

  13. Ultrafast Spectroscopy of Warm Dense Matter

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Spectroscopy of Warm Dense Matter Print Being neither solid, liquid, gas, nor plasma, warm dense matter (WDM) occupies a no man's land in the map of material phases. Its temperature can range between that of planetary cores (tens of thousands K) to that of stellar cores (hundreds of thousands K). Not only is it prevalent throughout the universe, it is relevant to inertial confinement fusion (ICF) and material performance under extreme conditions. However, because of its extreme temperatures and

  14. Spin noise spectroscopy of ZnO

    SciTech Connect (OSTI)

    Horn, H.; Berski, F.; Hbner, J.; Oestreich, M.; Balocchi, A.; Marie, X.; Mansur-Al-Suleiman, M.; Bakin, A.; Waag, A.

    2013-12-04

    We investigate the thermal equilibrium dynamics of electron spins bound to donors in nanoporous ZnO by optical spin noise spectroscopy. The spin noise spectra reveal two noise contributions: A weak spin noise signal from undisturbed localized donor electrons with a dephasing time of 24 ns due to hyperfine interaction and a strong spin noise signal with a spin dephasing time of 5 ns which we attribute to localized donor electrons which interact with lattice defects.

  15. Ultrafast Spectroscopy of Warm Dense Matter

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Ultrafast Spectroscopy of Warm Dense Matter Print Being neither solid, liquid, gas, nor plasma, warm dense matter (WDM) occupies a no man's land in the map of material phases. Its temperature can range between that of planetary cores (tens of thousands K) to that of stellar cores (hundreds of thousands K). Not only is it prevalent throughout the universe, it is relevant to inertial confinement fusion (ICF) and material performance under extreme conditions. However, because of its extreme

  16. Ultrafast Spectroscopy of Warm Dense Matter

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Ultrafast Spectroscopy of Warm Dense Matter Print Being neither solid, liquid, gas, nor plasma, warm dense matter (WDM) occupies a no man's land in the map of material phases. Its temperature can range between that of planetary cores (tens of thousands K) to that of stellar cores (hundreds of thousands K). Not only is it prevalent throughout the universe, it is relevant to inertial confinement fusion (ICF) and material performance under extreme conditions. However, because of its extreme

  17. Method and apparatus for time dispersive spectroscopy

    DOE Patents [OSTI]

    Tarver, III, Edward E.; Siems, William F.

    2003-06-17

    Methods and apparatus are described for time dispersive spectroscopy. In particular, a modulated flow of ionized molecules of a sample are introduced into a drift region of an ion spectrometer. The ions are subsequently detected by an ion detector to produce an ion detection signal. The ion detection signal can be modulated to obtain a signal useful in assaying the chemical constituents of the sample.

  18. Standoff spectroscopy using a conditioned target

    DOE Patents [OSTI]

    Van Neste, Charles W. (Kingston, TN); Morales-Rodriguez, Marissa E. (Knoxville, TN); Senesac, Lawrence R. (Knoxville, TN); Thundat, Thomas G. (Knoxville, TN)

    2011-12-20

    A system and method are disclosed for standoff spectroscopy of molecules (e.g. from a residue) on a surface from a distance. A source emits radiation that modifies or conditions the residue, such as through photodecomposition. A spectral generating source measures a spectrum of the residue before and after the residue is exposed to the radiation from that source. The two spectra are compared to produce a distinct identification of the residues on the surface or identify certain properties of the residue.

  19. Ecosystem Spectroscopy - Investigating associations between hyperspectral

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    optical data and ecosystem functions | Argonne Leadership Computing Facility Ecosystem Spectroscopy - Investigating associations between hyperspectral optical data and ecosystem functions Event Sponsor: Computation Institute Presentation Start Date: Jan 28 2016 - 12:00pm Building/Room: Searle 240A Location: The University of Chicago, 5735 S. Ellis Ave., webcast via Blue Jeans (see below) Speaker(s): Yuki Hamada Speaker(s) Title: Argonne National Labortory - ES Host: Rao Kotamarthi

  20. Computational Spectroscopy of Heterogeneous Interfaces | Argonne Leadership

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Computing Facility Complex interfaces between nanoparticles and a solvent Complex interfaces between nanoparticles and a solvent. N. Brawand, University of Chicago Computational Spectroscopy of Heterogeneous Interfaces PI Name: Giulia Galli PI Email: gagalli@uchicago.edu Institution: University of Chicago Allocation Program: INCITE Allocation Hours at ALCF: 150 Million Year: 2016 Research Domain: Materials Science The interfaces between solids, nanoparticles and liquids play a fundamental

  1. Theoretical aspects of light meson spectroscopy

    SciTech Connect (OSTI)

    Barnes, T. |

    1995-12-31

    In this pedagogical review the authors discuss the theoretical understanding of light hadron spectroscopy in terms of QCD and the quark model. They begin with a summary of the known and surmised properties of QCD and confinement. Following this they review the nonrelativistic quark potential model for q{anti q} mesons and discuss the quarkonium spectrum and methods for identifying q{anti q} states. Finally, they review theoretical expectations for non-q{anti q} states (glueballs, hybrids and multiquark systems) and the status of experimental candidates for these states.

  2. Method for conducting nonlinear electrochemical impedance spectroscopy

    DOE Patents [OSTI]

    Adler, Stuart B.; Wilson, Jamie R.; Huff, Shawn L.; Schwartz, Daniel T.

    2015-06-02

    A method for conducting nonlinear electrochemical impedance spectroscopy. The method includes quantifying the nonlinear response of an electrochemical system by measuring higher-order current or voltage harmonics generated by moderate-amplitude sinusoidal current or voltage perturbations. The method involves acquisition of the response signal followed by time apodization and fast Fourier transformation of the data into the frequency domain, where the magnitude and phase of each harmonic signal can be readily quantified. The method can be implemented on a computer as a software program.

  3. Analog detection for cavity lifetime spectroscopy

    DOE Patents [OSTI]

    Zare, Richard N. (Stanford, CA); Harb, Charles C. (Palo Alto, CA); Paldus, Barbara A. (Mountain View, CA); Spence, Thomas G. (Palo Alto, CA)

    2003-01-01

    An analog detection system for determining a ring-down rate or decay rate 1/.tau. of an exponentially decaying ring-down beam issuing from a lifetime or ring-down cavity during a ring-down phase. Alternatively, the analog detection system determines a build-up rate of an exponentially growing beam issuing from the cavity during a ring-up phase. The analog system can be employed in continuous wave cavity ring-down spectroscopy (CW CRDS) and pulsed CRDS (P CRDS) arrangements utilizing any type of ring-down cavity including ring-cavities and linear cavities.

  4. Cavity-locked ring down spectroscopy

    DOE Patents [OSTI]

    Zare, Richard N. (Stanford, CA); Paldus, Barbara A. (Stanford, CA); Harb, Charles C. (Palo Alto, CA); Spence, Thomas (Union City, CA)

    2000-01-01

    Distinct locking and sampling light beams are used in a cavity ring-down spectroscopy (CRDS) system to perform multiple ring-down measurements while the laser and ring-down cavity are continuously locked. The sampling and locking light beams have different frequencies, to ensure that the sampling and locking light are decoupled within the cavity. Preferably, the ring-down cavity is ring-shaped, the sampling light is s-polarized, and the locking light is p-polarized. Transmitted sampling light is used for ring-down measurements, while reflected locking light is used for locking in a Pound-Drever scheme.

  5. Analog detection for cavity lifetime spectroscopy

    DOE Patents [OSTI]

    Zare, Richard N. (Stanford, CA); Harb, Charles C. (Palo Alto, CA); Paldus, Barbara A. (Mountain View, CA); Spence, Thomas G. (Palo Alto, CA)

    2001-05-15

    An analog detection system for determining a ring-down rate or decay rate 1/.tau. of an exponentially decaying ring-down beam issuing from a lifetime or ring-down cavity during a ring-down phase. Alternatively, the analog detection system determines a build-up rate of an exponentially growing beam issuing from the cavity during a ring-up phase. The analog system can be employed in continuous wave cavity ring-down spectroscopy (CW CRDS) and pulsed CRDS (P CRDS) arrangements utilizing any type of ring-down cavity including ring-cavities and linear cavities.

  6. Mössbauer spectroscopy of Basal Ganglia

    SciTech Connect (OSTI)

    Miglierini, Marcel; Lančok, Adriana; Kopáni, Martin; Boča, Roman

    2014-10-27

    Chemical states, structural arrangement, and magnetic features of iron deposits in biological tissue of Basal Ganglia are characterized. The methods of SQUID magnetometry and electron microscopy are employed. {sup 57}Fe Mössbauer spectroscopy is used as a principal method of investigation. Though electron microscopy has unveiled robust crystals (1-3 μm in size) of iron oxides, they are not manifested in the corresponding {sup 57}Fe Mössbauer spectra. The latter were acquired at 300 K and 4.2 K and resemble ferritin-like behavior.

  7. B and D spectroscopy at LEP

    SciTech Connect (OSTI)

    Muheim, Franz

    1999-02-17

    Results from the four LEP experiments ALEPH, DELPHI, L3, and OPAL on the spectroscopy of B and charmed mesons are presented. The predictions of Heavy Quark Effective Theory (HQET) for the masses and the widths of excited L=1 B mesons are supported by a new measurement from L3. A few B{sub c}{sup +} candidate events have masses consistent with the recent CDF observation and the predictions. New results on D** production and B{yields}D**l{nu} are also presented. The evidence for a D*{sup '} meson reported recently by DELPHI is not supported by OPAL and CLEO.

  8. Beamline 11.0.2

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Endstations: Ambient-pressure photoemission spectroscopy Scanning transmission x-ray microscope (STXM) GENERAL BEAMLINE INFORMATION Operational Yes Source characteristics 5.0-cm...

  9. Dependence of Band Renormalization Effect on the Number of Copper...

    Office of Scientific and Technical Information (OSTI)

    DISPERSIONS; EXHIBITS; LAYERS; PHOTOEMISSION; RENORMALIZATION; SPECTROSCOPY; SUPERCONDUCTORS MATSCI Word Cloud More Like This Full Text preview image File size NAView Full ...

  10. Laser-induced breakdown spectroscopy at high temperatures in industrial

    Office of Scientific and Technical Information (OSTI)

    boilers and furnaces. (Journal Article) | SciTech Connect Laser-induced breakdown spectroscopy at high temperatures in industrial boilers and furnaces. Citation Details In-Document Search Title: Laser-induced breakdown spectroscopy at high temperatures in industrial boilers and furnaces. Laser-induced breakdown spectroscopy (LIBS) was applied (1) near the superheater of an electric power generation boiler burning biomass, coat, or both, (2) at the exit of a glass-melting furnace burning

  11. First Principles Calculations and NMR Spectroscopy of Electrode Materials |

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Department of Energy Materials First Principles Calculations and NMR Spectroscopy of Electrode Materials 2009 DOE Hydrogen Program and Vehicle Technologies Program Annual Merit Review and Peer Evaluation Meeting, May 18-22, 2009 -- Washington D.C. PDF icon es_27_grey.pdf More Documents & Publications First Principles Calculations and NMR Spectroscopy of Electrode Materials: NMR Vehicle Technologies Office Merit Review 2014: First Principles Calculations and NMR Spectroscopy of Electrode

  12. The 21st International Conference on Laser Spectroscopy - ICOLS...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    The 21st International Conference on Laser Spectroscopy - ICOLS 2013 http:icols.berkeley.edu June 9-14, 2013; Berkeley, CA...

  13. Optical Spectroscopy for Materials Applications | The Ames Laboratory

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Optical Spectroscopy for Materials Applications The two main objectives of the Smith research group are: (1) to measure the organization and dynamics of biological structures, and...

  14. The 21st International Conference on Laser Spectroscopy - ICOLS 2013

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    The 21st International Conference on Laser Spectroscopy - ICOLS 2013 http://icols.berkeley.edu/ June 9-14, 2013; Berkeley, CA

  15. X-ray transient absorption and picosecond IR spectroscopy of...

    Office of Scientific and Technical Information (OSTI)

    X-ray transient absorption and picosecond IR spectroscopy of fulvalene(tetracarbonyl)diruthenium on photoexcitation Citation Details In-Document Search Title: X-ray transient ...

  16. Report on the Feasibility of Pu Photoelectron Spectroscopy with...

    Office of Scientific and Technical Information (OSTI)

    Report on the Feasibility of Pu Photoelectron Spectroscopy with Microscopic and Nanoscopic Samples at NSLSII Citation Details In-Document Search Title: Report on the Feasibility of...

  17. First Principles Calculations and NMR Spectroscopy of Electrode...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Materials: NMR First Principles Calculations and NMR Spectroscopy of Electrode Materials: NMR 2010 DOE Vehicle Technologies and Hydrogen Programs Annual Merit Review and Peer...

  18. First Principles Calculations and NMR Spectroscopy of Electrode...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Materials First Principles Calculations and NMR Spectroscopy of Electrode Materials 2009 DOE Hydrogen Program and Vehicle Technologies Program Annual Merit Review and Peer...

  19. How electron spectroscopy with synchrotron light can help us...

    Office of Scientific and Technical Information (OSTI)

    Close How electron spectroscopy with synchrotron light can help us understand high tc superconductivity and other complex states of matter Zoom Video Closed Captions Info Title...

  20. XRMS: X-Ray Spectroscopy of Magnetic Solids

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    XRMS: X-Ray Spectroscopy of Magnetic Solids October 22-23, 2011 SLAC National Accelerator Laboratory, Menlo Park, CA More information...

  1. Standoff Spectroscopy Using a Conditioned Target Identifies Hazardous...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    the necessity of close and potentially hazardous contact. It combines tunable infrared (IR) and ultraviolet (UV) spectroscopy techniques to target identifying properties of...

  2. Multiplex coherent raman spectroscopy detector and method

    DOE Patents [OSTI]

    Chen, Peter; Joyner, Candace C.; Patrick, Sheena T.; Guyer, Dean R.

    2004-06-08

    A multiplex coherent Raman spectrometer (10) and spectroscopy method rapidly detects and identifies individual components of a chemical mixture separated by a separation technique, such as gas chromatography. The spectrometer (10) and method accurately identify a variety of compounds because they produce the entire gas phase vibrational Raman spectrum of the unknown gas. This is accomplished by tilting a Raman cell (20) to produce a high-intensity, backward-stimulated, coherent Raman beam of 683 nm, which drives a degenerate optical parametric oscillator (28) to produce a broadband beam of 1100-1700 nm covering a range of more than 3000 wavenumber. This broadband beam is combined with a narrowband beam of 532 nm having a bandwidth of 0.003 wavenumbers and focused into a heated windowless cell (38) that receives gases separated by a gas chromatograph (40). The Raman radiation scattered from these gases is filtered and sent to a monochromator (50) with multichannel detection.

  3. Spectroscopy, Kinetics, and Dynamics of Combustion Radicals

    SciTech Connect (OSTI)

    Nesbitt, David J.

    2013-08-06

    Spectroscopy, kinetics and dynamics of jet cooled hydrocarbon transients relevant to the DOE combustion mission have been explored, exploiting i) high resolution IR lasers, ii) slit discharge sources for formation of jet cooled radicals, and iii) high sensitivity detection with direct laser absorption methods and near the quantum shot noise limit. What makes this combination powerful is that such transients can be made under high concentrations and pressures characteristic of actual combustion conditions, and yet with the resulting species rapidly cooled (T ?10-15K) in the slit supersonic expansion. Combined with the power of IR laser absorption methods, this provides novel access to spectral detection and study of many critical combustion species.

  4. Deflecting light into resonant cavities for spectroscopy

    DOE Patents [OSTI]

    Zare, R.N.; Martin, J.; Paldus, B.A.

    1998-09-29

    Light is coupled into a cavity ring down spectroscopy (CRDS) resonant cavity using an acousto-optic modulator. The AOM allows in-coupling efficiencies in excess of 40%, which is two to three orders of magnitude higher than in conventional systems using a cavity mirror for in-coupling. The AOM shutoff time is shorter than the roundtrip time of the cavity. The higher light intensities lead to a reduction in shot noise, and allow the use of relatively insensitive but fast-responding detectors such as photovoltaic detectors. Other deflection devices such as electro-optic modulators or elements used in conventional Q-switching may be used instead of the AOM. The method is particularly useful in the mid-infrared, far-infrared, and ultraviolet wavelength ranges, for which moderately reflecting input mirrors are not widely available. 5 figs.

  5. Deflecting light into resonant cavities for spectroscopy

    DOE Patents [OSTI]

    Zare, Richard N. (Stanford, CA); Martin, Juergen (Harxheim, DE); Paldus, Barbara A. (Stanford, CA)

    1998-01-01

    Light is coupled into a cavity ring down spectroscopy (CRDS) resonant cavity using an acousto-optic modulator. The AOM allows in-coupling efficiencies in excess of 40%, which is two to three orders of magnitude higher than in conventional systems using a cavity mirror for in-coupling. The AOM shutoff time is shorter than the roundtrip time of the cavity. The higher light intensities lead to a reduction in shot noise, and allow the use of relatively insensitive but fast-responding detectors such as photovoltaic detectors. Other deflection devices such as electro-optic modulators or elements used in conventional Q-switching may be used instead of the AOM. The method is particularly useful in the mid-infrared, far-infrared, and ultraviolet wavelength ranges, for which moderately reflecting input mirrors are not widely available.

  6. Remote adjustable focus Raman spectroscopy probe

    DOE Patents [OSTI]

    Schmucker, John E.; Blasi, Raymond J.; Archer, William B.

    1999-01-01

    A remote adjustable focus Raman spectroscopy probe allows for analyzing Raman scattered light from a point of interest external probe. An environmental barrier including at least one window separates the probe from the point of interest. An optical tube is disposed adjacent to the environmental barrier and includes a long working length compound lens objective next to the window. A beam splitter and a mirror are at the other end. A mechanical means is used to translated the prove body in the X, Y, and Z directions resulting in a variable focus optical apparatus. Laser light is reflected by the beam splitter and directed toward the compound lens objective, then through the window and focused on the point of interest. Raman scattered light is then collected by the compound lens objective and directed through the beam splitter to a mirror. A device for analyzing the light, such as a monochrometer, is coupled to the mirror.

  7. Doping evolution of the electronic structure in the single-layer cuprates

    Office of Scientific and Technical Information (OSTI)

    Bi2Sr2- delta: Comparison with other single-layer cuprates (Journal Article) | SciTech Connect Doping evolution of the electronic structure in the single-layer cuprates Bi2Sr2&#8722xLaxCuO6 delta: Comparison with other single-layer cuprates Citation Details In-Document Search Title: Doping evolution of the electronic structure in the single-layer cuprates Bi2Sr2&#8722xLaxCuO6 delta: Comparison with other single-layer cuprates We have performed angle-resolved photoemission and

  8. Fermi arcs vs. fermi pockets in electron-doped perovskite iridates (Journal

    Office of Scientific and Technical Information (OSTI)

    Article) | SciTech Connect SciTech Connect Search Results Journal Article: Fermi arcs vs. fermi pockets in electron-doped perovskite iridates Citation Details In-Document Search Title: Fermi arcs vs. fermi pockets in electron-doped perovskite iridates We report on an angle resolved photoemission (ARPES) study of bulk electron-doped perovskite iridate, (Sr1-xLax)₃Ir₂O₇. Fermi surface pockets are observed with a total electron count in keeping with that expected from La substitution.

  9. Fermi arcs vs. fermi pockets in electron-doped perovskite iridates

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    He, Junfeng; Hafiz, H.; Mion, Thomas R.; Hogan, T.; Dhital, C.; Chen, X.; Lin, Qisen; Hashimoto, M.; Lu, D. H.; Zhang, Y.; et al

    2015-02-23

    We report on an angle resolved photoemission (ARPES) study of bulk electron-doped perovskite iridate, (Sr1-xLax)₃Ir₂O₇. Fermi surface pockets are observed with a total electron count in keeping with that expected from La substitution. Depending on the energy and polarization of the incident photons, these pockets show up in the form of disconnected “Fermi arcs”, reminiscent of those reported recently in surface electron-doped Sr₂IrO₄. Our observed spectral variation is consistent with the coexistence of an electronic supermodulation with structural distortion in the system.

  10. Hybridization and the effective mass of quantum-well states in magnetic multilayers

    SciTech Connect (OSTI)

    Johnson, P.D.; Garrison, K.; Dong, Q. ); Smith, N.V. ); Li, D.; Mattson, J.; Pearson, J.; Bader, S.D. )

    1994-09-15

    Angle-resolved-photoemission studies of the dispersion of the quantum-well states in copper thin films deposited on a Co(001) substrate reveal that hybridization in the interface leads to a large increase in the effective mass of the electrons. These observations have implications for theories of the oscillatory exchange coupling in the related magnetic multilayers, particularly where Fermi-surface spanning vectors away from the center of the zone are invoked as in the case of the short-period oscillation in the Co/Cu(001) multilayers.

  11. New Developments in the Theory of HTSC [High Temperature Superconductors

    DOE R&D Accomplishments [OSTI]

    Abrikosov, A.A.

    1994-09-01

    The superconductor is supposed to consist of alternating layers of two kinds: (1) layers with an attractive electron interaction and an effective mass of usual magnitude, (2) layers without interaction and with a large effective mass. The overlap between the layers is assumed to be small, its energy, t, being much less than {Delta}. It is shown, that such a model explains the most peculiar property found in experiments on electronic Raman light scattering in BSCCO 2212: different threshold values for the Raman satellite measured at two different polarizations of the incident and scattered light. The tunneling conductance G(V)= dJ/dV is analyzed for the same model. In order to fit the qualitative features of experimental data, it is assumed that the tunneling probability to the normal layers is much less, than to the superconducting layers. The conductance is calculated for the case t{much_lt}{Delta}. A brief analysis is given for the case t{approximately}{Delta}, which proves that such an assumption definitely contradicts the experimental data for BSCCO. The possible nature of the electronic states in the normal layers is discussed. In connection with the experimental discovery (angle resolved photoemission spectroscopy, ARPES) of the extended saddle point singularities in the electron spectrum of a variety of HTSC consequences are derived for T{sub c} and {Delta} in a simple model. A large enhancement of superconductivity is possible if the singularity has a sufficient extension and is located close to the Fermi energy. In order to explain the anisotropy of the energy gap, observed in ARPES experiments, on the basis of the "extended saddle point singularities" an assumption is done that the Coulomb interactions are weakly screened, i.e. the Debye screening radius is much larger than the lattice period; this makes the electron interaction long ranged (E-L model).

  12. Exotic/charmonium Hadron Spectroscopy at Belle and BaBar (Conference...

    Office of Scientific and Technical Information (OSTI)

    Conference: Exoticcharmonium Hadron Spectroscopy at Belle and BaBar Citation Details In-Document Search Title: Exoticcharmonium Hadron Spectroscopy at Belle and BaBar You are...

  13. Excited-state spectroscopy of singly, doubly and triply-charmed...

    Office of Scientific and Technical Information (OSTI)

    Conference: Excited-state spectroscopy of singly, doubly and triply-charmed baryons from lattice QCD Citation Details In-Document Search Title: Excited-state spectroscopy of...

  14. Terahertz magneto-optical spectroscopy of a two-dimensional hole...

    Office of Scientific and Technical Information (OSTI)

    DOE PAGES Search Results Accepted Manuscript: Terahertz magneto-optical spectroscopy of a two-dimensional hole gas Title: Terahertz magneto-optical spectroscopy of a...

  15. Magnetic spectroscopy and microscopy of functional materials

    SciTech Connect (OSTI)

    Jenkins, C.A.

    2011-01-28

    Heusler intermetallics Mn{sub 2}Y Ga and X{sub 2}MnGa (X; Y =Fe, Co, Ni) undergo tetragonal magnetostructural transitions that can result in half metallicity, magnetic shape memory, or the magnetocaloric effect. Understanding the magnetism and magnetic behavior in functional materials is often the most direct route to being able to optimize current materials for todays applications and to design novel ones for tomorrow. Synchrotron soft x-ray magnetic spectromicroscopy techniques are well suited to explore the the competing effects from the magnetization and the lattice parameters in these materials as they provide detailed element-, valence-, and site-specifc information on the coupling of crystallographic ordering and electronic structure as well as external parameters like temperature and pressure on the bonding and exchange. Fundamental work preparing the model systems of spintronic, multiferroic, and energy-related compositions is presented for context. The methodology of synchrotron spectroscopy is presented and applied to not only magnetic characterization but also of developing a systematic screening method for future examples of materials exhibiting any of the above effects. The chapter progression is as follows: an introduction to the concepts and materials under consideration (Chapter 1); an overview of sample preparation techniques and results, and the kinds of characterization methods employed (Chapter 2); spectro- and microscopic explorations of X{sub 2}MnGa/Ge (Chapter 3); spectroscopic investigations of the composition series Mn{sub 2}Y Ga to the logical Mn{sub 3}Ga endpoint (Chapter 4); and a summary and overview of upcoming work (Chapter 5). Appendices include the results of a Think Tank for the Graduate School of Excellence MAINZ (Appendix A) and details of an imaging project now in progress on magnetic reversal and domain wall observation in the classical Heusler material Co{sub 2}FeSi (Appendix B).

  16. Zero kinetic energy photoelectron spectroscopy of triphenylene

    SciTech Connect (OSTI)

    Harthcock, Colin; Zhang, Jie; Kong, Wei

    2014-06-28

    We report vibrational information of both the first electronically excited state and the ground cationic state of jet-cooled triphenylene via the techniques of resonantly enhanced multiphoton ionization (REMPI) and zero kinetic energy (ZEKE) photoelectron spectroscopy. The first excited electronic state S{sub 1} of the neutral molecule is of A{sub 1}? symmetry and is therefore electric dipole forbidden in the D{sub 3h} group. Consequently, there are no observable Franck-Condon allowed totally symmetric a{sub 1}? vibrational bands in the REMPI spectrum. All observed vibrational transitions are due to Herzberg-Teller vibronic coupling to the E? third electronically excited state S{sub 3}. The assignment of all vibrational bands as e? symmetry is based on comparisons with calculations using the time dependent density functional theory and spectroscopic simulations. When an electron is eliminated, the molecular frame undergoes Jahn-Teller distortion, lowering the point group to C{sub 2v} and resulting in two nearly degenerate electronic states of A{sub 2} and B{sub 1} symmetry. Here we follow a crude treatment by assuming that all e? vibrational modes resolve into b{sub 2} and a{sub 1} modes in the C{sub 2v} molecular frame. Some observed ZEKE transitions are tentatively assigned, and the adiabatic ionization threshold is determined to be 63?365 7 cm{sup ?1}. The observed ZEKE spectra contain a consistent pattern, with a cluster of transitions centered near the same vibrational level of the cation as that of the intermediate state, roughly consistent with the propensity rule. However, complete assignment of the detailed vibrational structure due to Jahn-Teller coupling requires much more extensive calculations, which will be performed in the future.

  17. Review of meson spectroscopy: quark states and glueballs

    SciTech Connect (OSTI)

    Chanowitz, M.S.

    1981-11-01

    A group of three lectures on hadron spectroscopy are presented. Topics covered include: light L = 0 mesons, light L = 1 mesons, antiquark antiquark quark quark exotics, a catalogue of higher quark antiquark excitations, heavy quarkonium, and glueballs. (GHT)

  18. Laser-induced breakdown spectroscopy of alkali metals in high...

    Office of Scientific and Technical Information (OSTI)

    alkali metals in high-temperature gas Citation Details In-Document Search Title: Laser-induced breakdown spectroscopy of alkali metals in high-temperature gas Laser-induced ...

  19. Ambient Pressure Photoelectron Spectroscopy Using Soft X-ray...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Ambient Pressure Photoelectron Spectroscopy Using Soft X-ray and Hard X-ray, and its applications in electrochemistry Friday, December 14, 2012 - 3:30pm SSRL, Bldg. 137, room 322...

  20. Dirac Charge Dynamcs in Graphene by Infrared Spectroscopy

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Dirac Charge Dynamcs in Graphene by Infrared Spectroscopy Print Graphene-a single layer of carbon atoms arranged in a honeycomb lattice-has very high conductivity that can be tuned...

  1. Dirac Charge Dynamcs in Graphene by Infrared Spectroscopy

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Dynamcs in Graphene by Infrared Spectroscopy Print Wednesday, 29 October 2008 00:00 Graphene-a single layer of carbon atoms arranged in a honeycomb lattice-has very high...

  2. Beamline 11.0.2

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    2 Print Molecular Environmental Science (MES) Scientific disciplines: Surface chemistry, environmental, planetary, biological, and medical sciences Endstations: Ambient-pressure photoemission spectroscopy Scanning transmission x-ray microscope (STXM) GENERAL BEAMLINE INFORMATION Operational Yes Source characteristics 5.0-cm period elliptical polarization undulator (EPU5) Energy range See endstation tables Monochromator See endstation tables Endstations Ambient-pressure photoemission spectroscopy

  3. Beamline 11.0.2

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    2 Print Molecular Environmental Science (MES) Scientific disciplines: Surface chemistry, environmental, planetary, biological, and medical sciences Endstations: Ambient-pressure photoemission spectroscopy Scanning transmission x-ray microscope (STXM) GENERAL BEAMLINE INFORMATION Operational Yes Source characteristics 5.0-cm period elliptical polarization undulator (EPU5) Energy range See endstation tables Monochromator See endstation tables Endstations Ambient-pressure photoemission spectroscopy

  4. Beamline 11.0.2

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    2 Print Molecular Environmental Science (MES) Scientific disciplines: Surface chemistry, environmental, planetary, biological, and medical sciences Endstations: Ambient-pressure photoemission spectroscopy Scanning transmission x-ray microscope (STXM) GENERAL BEAMLINE INFORMATION Operational Yes Source characteristics 5.0-cm period elliptical polarization undulator (EPU5) Energy range See endstation tables Monochromator See endstation tables Endstations Ambient-pressure photoemission spectroscopy

  5. Beamline 11.0.2

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    2 Print Molecular Environmental Science (MES) Scientific disciplines: Surface chemistry, environmental, planetary, biological, and medical sciences Endstations: Ambient-pressure photoemission spectroscopy Scanning transmission x-ray microscope (STXM) GENERAL BEAMLINE INFORMATION Operational Yes Source characteristics 5.0-cm period elliptical polarization undulator (EPU5) Energy range See endstation tables Monochromator See endstation tables Endstations Ambient-pressure photoemission spectroscopy

  6. Beamline 11.0.2

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    2 Print Molecular Environmental Science (MES) Scientific disciplines: Surface chemistry, environmental, planetary, biological, and medical sciences Endstations: Ambient-pressure photoemission spectroscopy Scanning transmission x-ray microscope (STXM) GENERAL BEAMLINE INFORMATION Operational Yes Source characteristics 5.0-cm period elliptical polarization undulator (EPU5) Energy range See endstation tables Monochromator See endstation tables Endstations Ambient-pressure photoemission spectroscopy

  7. Beamline 11.0.2

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    2 Print Molecular Environmental Science (MES) Scientific disciplines: Surface chemistry, environmental, planetary, biological, and medical sciences Endstations: Ambient-pressure photoemission spectroscopy Scanning transmission x-ray microscope (STXM) GENERAL BEAMLINE INFORMATION Operational Yes Source characteristics 5.0-cm period elliptical polarization undulator (EPU5) Energy range See endstation tables Monochromator See endstation tables Endstations Ambient-pressure photoemission spectroscopy

  8. Beamline 11.0.2

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    2 Print Molecular Environmental Science (MES) Scientific disciplines: Surface chemistry, environmental, planetary, biological, and medical sciences Endstations: Ambient-pressure photoemission spectroscopy Scanning transmission x-ray microscope (STXM) GENERAL BEAMLINE INFORMATION Operational Yes Source characteristics 5.0-cm period elliptical polarization undulator (EPU5) Energy range See endstation tables Monochromator See endstation tables Endstations Ambient-pressure photoemission spectroscopy

  9. Beamline 11.0.2

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    2 Print Molecular Environmental Science (MES) Scientific disciplines: Surface chemistry, environmental, planetary, biological, and medical sciences Endstations: Ambient-pressure photoemission spectroscopy Scanning transmission x-ray microscope (STXM) GENERAL BEAMLINE INFORMATION Operational Yes Source characteristics 5.0-cm period elliptical polarization undulator (EPU5) Energy range See endstation tables Monochromator See endstation tables Endstations Ambient-pressure photoemission spectroscopy

  10. Beamline 11.0.2

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    2 Print Molecular Environmental Science (MES) Scientific disciplines: Surface chemistry, environmental, planetary, biological, and medical sciences Endstations: Ambient-pressure photoemission spectroscopy Scanning transmission x-ray microscope (STXM) GENERAL BEAMLINE INFORMATION Operational Yes Source characteristics 5.0-cm period elliptical polarization undulator (EPU5) Energy range See endstation tables Monochromator See endstation tables Endstations Ambient-pressure photoemission spectroscopy

  11. Beamline 11.0.2

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    2 Print Molecular Environmental Science (MES) Scientific disciplines: Surface chemistry, environmental, planetary, biological, and medical sciences Endstations: Ambient-pressure photoemission spectroscopy Scanning transmission x-ray microscope (STXM) GENERAL BEAMLINE INFORMATION Operational Yes Source characteristics 5.0-cm period elliptical polarization undulator (EPU5) Energy range See endstation tables Monochromator See endstation tables Endstations Ambient-pressure photoemission spectroscopy

  12. Beamline 11.0.2

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    2 Print Molecular Environmental Science (MES) Scientific disciplines: Surface chemistry, environmental, planetary, biological, and medical sciences Endstations: Ambient-pressure photoemission spectroscopy Scanning transmission x-ray microscope (STXM) GENERAL BEAMLINE INFORMATION Operational Yes Source characteristics 5.0-cm period elliptical polarization undulator (EPU5) Energy range See endstation tables Monochromator See endstation tables Endstations Ambient-pressure photoemission spectroscopy

  13. Beamline 11.0.2

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    2 Print Molecular Environmental Science (MES) Scientific disciplines: Surface chemistry, environmental, planetary, biological, and medical sciences Endstations: Ambient-pressure photoemission spectroscopy Scanning transmission x-ray microscope (STXM) GENERAL BEAMLINE INFORMATION Operational Yes Source characteristics 5.0-cm period elliptical polarization undulator (EPU5) Energy range See endstation tables Monochromator See endstation tables Endstations Ambient-pressure photoemission spectroscopy

  14. Impedance spectroscopy of organic magnetoresistance devices-Effect of

    Office of Scientific and Technical Information (OSTI)

    interface disorder (Journal Article) | SciTech Connect Impedance spectroscopy of organic magnetoresistance devices-Effect of interface disorder Citation Details In-Document Search Title: Impedance spectroscopy of organic magnetoresistance devices-Effect of interface disorder Organic magnetoresistance (OMAR) can be caused by either single carrier (bipolaron) or double carriers (electron-hole)-based mechanisms. In order to consider applications for OMAR, it is important to control the

  15. Reflectance spectroscopy for high-speed temperature measurements.

    Office of Scientific and Technical Information (OSTI)

    (Conference) | SciTech Connect SciTech Connect Search Results Conference: Reflectance spectroscopy for high-speed temperature measurements. Citation Details In-Document Search Title: Reflectance spectroscopy for high-speed temperature measurements. Abstract not provided. Authors: Dolan, Daniel H., ; Seagle, Christopher T ; Ao, Tommy ; Herrmann, Mark Publication Date: 2013-05-01 OSTI Identifier: 1106087 Report Number(s): SAND2013-3898C 465305 DOE Contract Number: AC04-94AL85000 Resource Type:

  16. Dirac Charge Dynamcs in Graphene by Infrared Spectroscopy

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Dirac Charge Dynamcs in Graphene by Infrared Spectroscopy Dirac Charge Dynamcs in Graphene by Infrared Spectroscopy Print Wednesday, 29 October 2008 00:00 Graphene-a single layer of carbon atoms arranged in a honeycomb lattice-has very high conductivity that can be tuned by applying a gate voltage. The charge carriers in graphene can travel ballistically over great distances (~1 micron) without scattering. These unusual electronic properties make graphene a promising candidate for future

  17. NSS-8 Workshop Summary International Workshop on Nanoscale Spectroscopy and

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Nanotechnology | Argonne National Laboratory NSS-8 Workshop Summary International Workshop on Nanoscale Spectroscopy and Nanotechnology August 1, 2014 Tweet EmailPrint Organized by Center for Nanoscale Materials and Advanced Photon Source The International Workshop on Nanoscale Spectroscopy and Nanotechnology 8 (NSS-8), organized by the Center for Nanoscale Materials (CNM) and Advanced Photon Source (APS), was held under sunny, summer skies from July 28-31, 2014, in the world-class Gleacher

  18. Combining Feedback Absorption Spectroscopy, Amplified Resonance and Low

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Pressure Sampling for the Measurement of Nitrogen-Containing Compounds in Automotive Emissions | Department of Energy Feedback Absorption Spectroscopy, Amplified Resonance and Low Pressure Sampling for the Measurement of Nitrogen-Containing Compounds in Automotive Emissions Combining Feedback Absorption Spectroscopy, Amplified Resonance and Low Pressure Sampling for the Measurement of Nitrogen-Containing Compounds in Automotive Emissions Discusses a novel combination of multi-component

  19. Report on the Feasibility of Pu Photoelectron Spectroscopy with Microscopic

    Office of Scientific and Technical Information (OSTI)

    and Nanoscopic Samples at NSLSII (Technical Report) | SciTech Connect Report on the Feasibility of Pu Photoelectron Spectroscopy with Microscopic and Nanoscopic Samples at NSLSII Citation Details In-Document Search Title: Report on the Feasibility of Pu Photoelectron Spectroscopy with Microscopic and Nanoscopic Samples at NSLSII Authors: Tobin, J G Publication Date: 2012-09-11 OSTI Identifier: 1053685 Report Number(s): LLNL-TR-582213 DOE Contract Number: W-7405-ENG-48 Resource Type:

  20. THRESHOLD RADIOACTIVITY FOR BULK FOOD SAMPLES BY GAMMA SPECTROSCOPY

    Office of Scientific and Technical Information (OSTI)

    (Journal Article) | SciTech Connect THRESHOLD RADIOACTIVITY FOR BULK FOOD SAMPLES BY GAMMA SPECTROSCOPY Citation Details In-Document Search Title: THRESHOLD RADIOACTIVITY FOR BULK FOOD SAMPLES BY GAMMA SPECTROSCOPY Authors: Yakabe, H.M. ; Neilson, H. Publication Date: 1965-02-01 OSTI Identifier: 4654936 Resource Type: Journal Article Resource Relation: Journal Name: J. Assoc. Offic. Agr. Chemists; Journal Volume: Vol: 48; Other Information: Orig. Receipt Date: 31-DEC-65 Research Org: Div. of

  1. Universality in Higher Order Spin Noise Spectroscopy (Journal Article) |

    Office of Scientific and Technical Information (OSTI)

    SciTech Connect Universality in Higher Order Spin Noise Spectroscopy Citation Details In-Document Search This content will become publicly available on January 14, 2017 Title: Universality in Higher Order Spin Noise Spectroscopy Authors: Li, Fuxiang ; Sinitsyn, N. A. Publication Date: 2016-01-15 OSTI Identifier: 1235627 Grant/Contract Number: AC52-06NA25396 Type: Publisher's Accepted Manuscript Journal Name: Physical Review Letters Additional Journal Information: Journal Volume: 116; Journal

  2. Update on Establishing the Feasibility of Lead Slowing Down Spectroscopy

    Office of Scientific and Technical Information (OSTI)

    for Direct Measurement of Plutonium in Used Fuel (Conference) | SciTech Connect Conference: Update on Establishing the Feasibility of Lead Slowing Down Spectroscopy for Direct Measurement of Plutonium in Used Fuel Citation Details In-Document Search Title: Update on Establishing the Feasibility of Lead Slowing Down Spectroscopy for Direct Measurement of Plutonium in Used Fuel Developing a method for the accurate, direct, and independent assay of the fissile isotopes in bulk materials (such

  3. X-ray transient absorption and picosecond IR spectroscopy of

    Office of Scientific and Technical Information (OSTI)

    fulvalene(tetracarbonyl)diruthenium on photoexcitation (Journal Article) | SciTech Connect X-ray transient absorption and picosecond IR spectroscopy of fulvalene(tetracarbonyl)diruthenium on photoexcitation Citation Details In-Document Search Title: X-ray transient absorption and picosecond IR spectroscopy of fulvalene(tetracarbonyl)diruthenium on photoexcitation Authors: Harpham, M. R. ; Nguyen, S. C. ; Hou, Z. ; Grossman, J. C. ; Harris, C. B. ; Mara, M. W. ; Stickrath, A. B. ; Kanai, Y. ;

  4. Femtosecond Coherent Anti-Stokes Raman Spectroscopy (CARS) As Next Generation Nonlinear LIDAR Spectroscopy and Microscopy

    SciTech Connect (OSTI)

    Ooi, C. H. Raymond

    2009-07-10

    Nonlinear spectroscopy using coherent anti-Stokes Raman scattering and femtosecond laser pulses has been successfully developed as powerful tools for chemical analysis and biological imaging. Recent developments show promising possibilities of incorporating CARS into LIDAR system for remote detection of molecular species in airborne particles. The corresponding theory is being developed to describe nonlinear scattering of a mesoscopic particle composed of complex molecules by laser pulses with arbitrary shape and spectral content. Microscopic many-body transform theory is used to compute the third order susceptibility for CARS in molecules with known absorption spectrum and vibrational modes. The theory is combined with an integral scattering formula and Mie-Lorentz formulae, giving a rigorous formalism which provides powerful numerical experimentation of CARS spectra, particularly on the variations with the laser parameters and the direction of detection.

  5. In Situ Diffuse Reflectance IR Spectroscopy and X-ray Absorption Spectroscopy for Fast Catalytic Processes

    SciTech Connect (OSTI)

    N Marinkovic; Q Wang; A Frenkel

    2011-12-31

    A new instrument for synchronous in situ investigations of catalytic materials by IR and X-ray absorption spectroscopies was designed and built at the X18A beamline of the National Synchrotron Light Source of Brookhaven National Laboratory. It provides analytical tools for solving structural, electronic and kinetic problems in catalysis science by two complementary methods. Among the features attractive for catalysis research are the broad range of catalytically active elements that can be investigated (starting with Ni and beyond), the wide range of reaction conditions (temperatures up to 873 K, various reactive gases) and time scales (starting from tens of seconds). The results of several representative experiments that illustrate the attractive capabilities of the new set-up are discussed.

  6. Study of asymmetries of Cd(Zn)Te devices investigated using photo-induced current transient spectroscopy, Rutherford backscattering, surface photo-voltage spectroscopy, and gamma ray spectroscopies

    SciTech Connect (OSTI)

    Crocco, J.; Bensalah, H.; Zheng, Q.; Dieguez, E.; Corregidor, V.; Avles, E.; Castaldini, A.; Fraboni, B.; Cavalcoli, D.; Cavallini, A.; Vela, O.

    2012-10-01

    Despite these recent advancements in preparing the surface of Cd(Zn)Te devices for detector applications, large asymmetries in the electronic properties of planar Cd(Zn)Te detectors are common. Furthermore, for the development of patterned electrode geometries, selection of each electrode surface is crucial for minimizing dark current in the device. This investigation presented here has been carried out with three objectives. Each objective is oriented towards establishing reliable methods for the selection of the anode and cathode surfaces independent of the crystallographic orientation. The objectives of this study are (i) investigate how the asymmetry in I-V characteristics of Cd(Zn)Te devices may be associated with the TeO2 interfacial layer using Rutherford backscattering to study the structure at the Au-Cd(Zn)Te interface, (ii) develop an understanding of how the concentration of the active traps in Cd(Zn)Te varies with the external bias, and (iii) propose non-destructive methods for selection of the anode and cathode which are independent of crystallographic orientation. The spectroscopic methods employed in this investigation include Rutherford backscattering spectroscopy, photo-induced current transient spectroscopy, and surface photo-voltage spectroscopy, as well as gamma ray spectroscopy to demonstrate the influence on detector properties.

  7. Indium diffusion through high-k dielectrics in high-k/InP stacks

    SciTech Connect (OSTI)

    Dong, H.; Cabrera, W.; Santosh KC,; Brennan, B.; Qin, X.; McDonnell, S.; Hinkle, C. L.; Cho, K.; Chabal, Y. J.; Galatage, R. V.; Zhernokletov, D.; Wallace, R. M.; Department of Physics, University of Texas at Dallas, Richardson, Texas 75080

    2013-08-05

    Evidence of indium diffusion through high-k dielectric (Al{sub 2}O{sub 3} and HfO{sub 2}) films grown on InP (100) by atomic layer deposition is observed by angle resolved X-ray photoelectron spectroscopy and low energy ion scattering spectroscopy. The analysis establishes that In-out diffusion occurs and results in the formation of a PO{sub x} rich interface.

  8. Beamline 10.0.1

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    0.1 Print Angle- and Spin-Resolved Photoelectron Spectroscopy of Solids Scientific disciplines: Strongly correlated electron systems, magnetism Endstations: High energy resolution spectrometer (HERS) Spin- and angle-resolved photoelectron spectroscopy (Spin-ARPES) GENERAL BEAMLINE INFORMATION Operational Yes Source characteristics 10-cm period undulator (U10) (first and third harmonics) Energy range 17-350 eV Monochromator Spherical grating monochromator (380, 925, 2100 lines/mm gratings)

  9. Beamline 10.0.1

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    0.1 Print Angle- and Spin-Resolved Photoelectron Spectroscopy of Solids Scientific disciplines: Strongly correlated electron systems, magnetism Endstations: High energy resolution spectrometer (HERS) Spin- and angle-resolved photoelectron spectroscopy (Spin-ARPES) GENERAL BEAMLINE INFORMATION Operational Yes Source characteristics 10-cm period undulator (U10) (first and third harmonics) Energy range 17-350 eV Monochromator Spherical grating monochromator (380, 925, 2100 lines/mm gratings)

  10. Beamline 10.0.1

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    0.1 Print Angle- and Spin-Resolved Photoelectron Spectroscopy of Solids Scientific disciplines: Strongly correlated electron systems, magnetism Endstations: High energy resolution spectrometer (HERS) Spin- and angle-resolved photoelectron spectroscopy (Spin-ARPES) GENERAL BEAMLINE INFORMATION Operational Yes Source characteristics 10-cm period undulator (U10) (first and third harmonics) Energy range 17-350 eV Monochromator Spherical grating monochromator (380, 925, 2100 lines/mm gratings)

  11. Beamline 10.0.1

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    0.1 Print Angle- and Spin-Resolved Photoelectron Spectroscopy of Solids Scientific disciplines: Strongly correlated electron systems, magnetism Endstations: High energy resolution spectrometer (HERS) Spin- and angle-resolved photoelectron spectroscopy (Spin-ARPES) GENERAL BEAMLINE INFORMATION Operational Yes Source characteristics 10-cm period undulator (U10) (first and third harmonics) Energy range 17-350 eV Monochromator Spherical grating monochromator (380, 925, 2100 lines/mm gratings)

  12. Beamline 10.0.1

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    0.1 Print Angle- and Spin-Resolved Photoelectron Spectroscopy of Solids Scientific disciplines: Strongly correlated electron systems, magnetism Endstations: High energy resolution spectrometer (HERS) Spin- and angle-resolved photoelectron spectroscopy (Spin-ARPES) GENERAL BEAMLINE INFORMATION Operational Yes Source characteristics 10-cm period undulator (U10) (first and third harmonics) Energy range 17-350 eV Monochromator Spherical grating monochromator (380, 925, 2100 lines/mm gratings)

  13. Beamline 10.0.1

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    0.1 Print Angle- and Spin-Resolved Photoelectron Spectroscopy of Solids Scientific disciplines: Strongly correlated electron systems, magnetism Endstations: High energy resolution spectrometer (HERS) Spin- and angle-resolved photoelectron spectroscopy (Spin-ARPES) GENERAL BEAMLINE INFORMATION Operational Yes Source characteristics 10-cm period undulator (U10) (first and third harmonics) Energy range 17-350 eV Monochromator Spherical grating monochromator (380, 925, 2100 lines/mm gratings)

  14. Beamline 10.0.1

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    0.1 Print Angle- and Spin-Resolved Photoelectron Spectroscopy of Solids Scientific disciplines: Strongly correlated electron systems, magnetism Endstations: High energy resolution spectrometer (HERS) Spin- and angle-resolved photoelectron spectroscopy (Spin-ARPES) GENERAL BEAMLINE INFORMATION Operational Yes Source characteristics 10-cm period undulator (U10) (first and third harmonics) Energy range 17-350 eV Monochromator Spherical grating monochromator (380, 925, 2100 lines/mm gratings)

  15. 2012 ELECTRONIC SPECTROSCOPY & DYNAMICS GORDON RESEARCH CONFERENCE, JULY 22-27, 2012

    SciTech Connect (OSTI)

    Kohler, Bern

    2012-07-27

    Topics covered in this GRC include high-resolution spectroscopy, coherent electronic energy transport in biology, excited state theory and dynamics, excitonics, electronic spectroscopy of cold and ultracold molecules, and the spectroscopy of nanostructures. Several sessions will highlight innovative techniques such as time-resolved x-ray spectroscopy, frequency combs, and liquid microjet photoelectron spectroscopy that have forged stimulating new connections between gas-phase and condensed-phase work.

  16. Electronic structure of the heavy-fermion caged compound Ce3Pd20X6(X=Si,Ge) studied by density functional theory and photoelectron spectroscopy

    SciTech Connect (OSTI)

    Yamaoka, Hitoshi; Schwier, Eike F.; Arita, Masashi; Shimada, Kenya; Tsujii, Naohito; Jarrige, Ignace; Jiang, Jian; Hayashi, Hirokazu; Iwasawa, Hideaki; Namatame, Hirofumi; Taniguchi, Masaki; Kitazawa, Hideaki

    2015-03-30

    The electronic structure of Ce₃Pd₂₀X₆ (X = Si, Ge) has been studied using detailed density functional theory (DFT) calculations and high-resolution photoelectron spectroscopy (PES) measurements. The orbital decomposition of the electronic structure by DFT calculations indicates that Ce atoms at the (8c) site surrounded by 16 Pd atoms have a more localized nature and a tendency to be magnetic. Ce atoms in the (4a) site surrounded by 12 Pd and 6 X atoms, on the other, show only a negligible magnetic moment. In the photoemission valence-band spectra we observe a strong f⁰ (Ce⁴⁺) component with a small fraction of f¹ (Ce³⁺) component. The spectral weight of f¹ component near the Fermi level Ce₃Pd₂₀Si₆ is stronger than that for Ce₃Pd₂₀Ge₆ at the 4d-4f resonance, suggesting stronger c-f hybridization in the former. This may hint to the origin of the large electronic specific coefficient of Ce₃Pd₂₀Si₆ compared to Ce₃Pd₂₀Ge₆.

  17. Analysis Tools for Next-Generation Hadron Spectroscopy Experiments

    SciTech Connect (OSTI)

    Battaglieri, Marco; Briscoe, William; Celentano, Andrea; Chung, Suh-Urk; D'Angelo, Annalisa; De Vita, Rafaella; Döring, Michael; Dudek, Jozef; Eidelman, S.; Fegan, Stuart; Ferretti, J.; Filippi, A.; Fox, G.; Galata, G.; García-Tecocoatzi, H.; Glazier, Derek; Grube, B.; Hanhart, C.; Hoferichter, M.; Hughes, S. M.; Ireland, David G.; Ketzer, B.; Klein, Franz J.; Kubis, B.; Liu, B.; Masjuan, P.; Mathieu, Vincent; McKinnon, Brian; Mitchel, R.; Nerling, F.; Paul, S.; Peláez, J. R.; Rademacker, J.; Rizzo, Alessandro; Salgado, Carlos; Santopinto, E.; Sarantsev, Andrey V.; Sato, Toru; Schlüter, T.; da Silva, M. L.L.; Stankovic, I.; Strakovsky, Igor; Szczepaniak, Adam; Vassallo, A.; Walford, Natalie K.; Watts, Daniel P.

    2015-01-01

    The series of workshops on New Partial-Wave Analysis Tools for Next-Generation Hadron Spectroscopy Experiments was initiated with the ATHOS 2012 meeting, which took place in Camogli, Italy, June 20-22, 2012. It was followed by ATHOS 2013 in Kloster Seeon near Munich, Germany, May 21-24, 2013. The third, ATHOS3, meeting is planned for April 13-17, 2015 at The George Washington University Virginia Science and Technology Campus, USA. The workshops focus on the development of amplitude analysis tools for meson and baryon spectroscopy, and complement other programs in hadron spectroscopy organized in the recent past including the INT-JLab Workshop on Hadron Spectroscopy in Seattle in 2009, the International Workshop on Amplitude Analysis in Hadron Spectroscopy at the ECT*-Trento in 2011, the School on Amplitude Analysis in Modern Physics in Bad Honnef in 2011, the Jefferson Lab Advanced Study Institute Summer School in 2012, and the School on Concepts of Modern Amplitude Analysis Techniques in Flecken-Zechlin near Berlin in September 2013. The aim of this document is to summarize the discussions that took place at the ATHOS 2012 and ATHOS 2013 meetings. We do not attempt a comprehensive review of the field of amplitude analysis, but offer a collection of thoughts that we hope may lay the ground for such a document.

  18. Hyper-Ramsey spectroscopy of optical clock transitions

    SciTech Connect (OSTI)

    Yudin, V. I.; Taichenachev, A. V.; Oates, C. W.; Barber, Z. W.; Lemke, N. D.; Ludlow, A. D.; Sterr, U.; Lisdat, Ch.; Riehle, F. [Institute of Laser Physics, Siberian Branch of Russian Academy of Sciences, Novosibirsk 630090, Russia, Novosibirsk State University, Novosibirsk 630090, Russia, and Novosibirsk State Technical University, Novosibirsk 630092 (Russian Federation); National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305 (United States); Physikalisch-Technische Bundesanstalt (PTB), Bundesallee 100, D-38116 Braunschweig (Germany)

    2010-07-15

    We present nonstandard optical Ramsey schemes that use pulses individually tailored in duration, phase, and frequency to cancel spurious frequency shifts related to the excitation itself. In particular, the field shifts and their uncertainties can be radically suppressed (by two to four orders of magnitude) in comparison with the usual Ramsey method (using two equal pulses) as well as with single-pulse Rabi spectroscopy. Atom interferometers and optical clocks based on two-photon transitions, heavily forbidden transitions, or magnetically induced spectroscopy could significantly benefit from this method. In the latter case, these frequency shifts can be suppressed considerably below a fractional level of 10{sup -17}. Moreover, our approach opens the door for high-precision optical clocks based on direct frequency comb spectroscopy.

  19. 2010 GRC VIBRATIONAL SPECTROSCOPY AUGUST 1 - AUGUST 6, 2010

    SciTech Connect (OSTI)

    Brooks Pate

    2010-08-06

    The Vibrational Spectroscopy conference focuses on using vibrational spectroscopy to probe structure and dynamics of molecules in gases, liquids, and at interfaces. The conference explores the wide range of state-of-the-art techniques based on vibrational motion. These techniques span the fields of time-domain, high-resolution frequency-domain, spatially-resolved, nonlinear and multidimensional spectroscopies. The conference highlights the application of these techniques in chemistry, materials, biology, and medicine. The theory of molecular vibrational motion and its connection to spectroscopic signatures and chemical reaction dynamics is the third major theme of the meeting. The goal is to bring together a collection of researchers who share common interests and who will gain from discussing work at the forefront of several connected areas. The intent is to emphasize the insights and understanding that studies of vibrations provide about a variety of molecular systems ranging from small polyatomic molecules to large biomolecules and nanomaterials.

  20. High resolution absorption spectroscopy of exploding wire plasmas using an

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    x-pinch x-ray source and spherically bent crystal (Journal Article) | DOE PAGES High resolution absorption spectroscopy of exploding wire plasmas using an x-pinch x-ray source and spherically bent crystal Title: High resolution absorption spectroscopy of exploding wire plasmas using an x-pinch x-ray source and spherically bent crystal Authors: Knapp, P. F. [1] ; Pikuz, S. A. [1] ; Shelkovenko, T. A. [1] ; Hammer, D. A. [1] ; Hansen, S. B. [2] + Show Author Affiliations Laboratory of Plasma

  1. High resolution absorption spectroscopy of exploding wire plasmas using an

    Office of Scientific and Technical Information (OSTI)

    x-pinch x-ray source and spherically bent crystal (Journal Article) | DOE PAGES Published Article: High resolution absorption spectroscopy of exploding wire plasmas using an x-pinch x-ray source and spherically bent crystal Title: High resolution absorption spectroscopy of exploding wire plasmas using an x-pinch x-ray source and spherically bent crystal Authors: Knapp, P. F. [1] ; Pikuz, S. A. [1] ; Shelkovenko, T. A. [1] ; Hammer, D. A. [1] ; Hansen, S. B. [2] + Show Author Affiliations

  2. Spectroscopy and Decay of $B$ Hadrons at the Tevatron

    SciTech Connect (OSTI)

    Paulini, Manfred

    2007-02-01

    The authors review recent results on heavy quark physics focusing on Run II measurements of B hadron spectroscopy and decay at the Tevatron. A wealth of new B physics measurements from CDF and D0 has been available. These include the spectroscopy of excited B states (B**, B**{sub s}) and the observation of the {Sigma}{sub b} baryon. The discussion of the decays of B hadrons and measurements of branching fractions focuses on charmless two-body decays of B {yields} h{sup +}h{sup -}. They report several new B{sub s}{sup 0} and {Lambda}{sub b}{sup 0} decay channels.

  3. Summary of the working group 4: Hadron spectroscopy

    SciTech Connect (OSTI)

    Crowe, K.M.

    1991-03-01

    This report is a summary of the working group 4 on hadron spectroscopy. The topics covered are: physics motivation; design of spectrometer; status of some existing hadron spectrometers; improvements to LASS; and arguments for/against a LASS-like design.

  4. Infrared Spectroscopy of Explosives Residues: Measurement Techniques and Spectral Analysis

    SciTech Connect (OSTI)

    Phillips, Mark C.; Bernacki, Bruce E.

    2015-03-11

    Infrared laser spectroscopy of explosives is a promising technique for standoff and non-contact detection applications. However, the interpretation of spectra obtained in typical standoff measurement configurations presents numerous challenges. Understanding the variability in observed spectra from explosives residues and particles is crucial for design and implementation of detection algorithms with high detection confidence and low false alarm probability. We discuss a series of infrared spectroscopic techniques applied toward measuring and interpreting the reflectance spectra obtained from explosives particles and residues. These techniques utilize the high spectral radiance, broad tuning range, rapid wavelength tuning, high scan reproducibility, and low noise of an external cavity quantum cascade laser (ECQCL) system developed at Pacific Northwest National Laboratory. The ECQCL source permits measurements in configurations which would be either impractical or overly time-consuming with broadband, incoherent infrared sources, and enables a combination of rapid measurement speed and high detection sensitivity. The spectroscopic methods employed include standoff hyperspectral reflectance imaging, quantitative measurements of diffuse reflectance spectra, reflection-absorption infrared spectroscopy, microscopic imaging and spectroscopy, and nano-scale imaging and spectroscopy. Measurements of explosives particles and residues reveal important factors affecting observed reflectance spectra, including measurement geometry, substrate on which the explosives are deposited, and morphological effects such as particle shape, size, orientation, and crystal structure.

  5. Analysis Tools for Next-Generation Hadron Spectroscopy Experiments

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Battaglieri, Marco; Briscoe, William; Celentano, Andrea; Chung, Suh-Urk; D'Angelo, Annalisa; De Vita, Rafaella; Döring, Michael; Dudek, Jozef; Eidelman, S.; Fegan, Stuart; et al

    2015-01-01

    The series of workshops on New Partial-Wave Analysis Tools for Next-Generation Hadron Spectroscopy Experiments was initiated with the ATHOS 2012 meeting, which took place in Camogli, Italy, June 20-22, 2012. It was followed by ATHOS 2013 in Kloster Seeon near Munich, Germany, May 21-24, 2013. The third, ATHOS3, meeting is planned for April 13-17, 2015 at The George Washington University Virginia Science and Technology Campus, USA. The workshops focus on the development of amplitude analysis tools for meson and baryon spectroscopy, and complement other programs in hadron spectroscopy organized in the recent past including the INT-JLab Workshop on Hadron Spectroscopymore » in Seattle in 2009, the International Workshop on Amplitude Analysis in Hadron Spectroscopy at the ECT*-Trento in 2011, the School on Amplitude Analysis in Modern Physics in Bad Honnef in 2011, the Jefferson Lab Advanced Study Institute Summer School in 2012, and the School on Concepts of Modern Amplitude Analysis Techniques in Flecken-Zechlin near Berlin in September 2013. The aim of this document is to summarize the discussions that took place at the ATHOS 2012 and ATHOS 2013 meetings. We do not attempt a comprehensive review of the field of amplitude analysis, but offer a collection of thoughts that we hope may lay the ground for such a document.« less

  6. Spectroscopy of triply and quadruply ionized states of mercury

    SciTech Connect (OSTI)

    Huttula, M.; Huttula, S.-M.; Lablanquie, P.; Palaudoux, J.; Penent, F.; Andric, L.; Eland, J. H. D.

    2011-03-15

    Multielectron coincidence spectroscopy has been used to study multiple ionization of atomic mercury. The binding energies of triply and quadruply ionized states of Hg have been determined from three- and fourfold electron coincidences. Relativistic ab initio theory has been used to calculate the state energies and predict the experimental findings.

  7. Improved Laser Induced Breakdown Spectroscopy (LIBS) Elemental Composition

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Detection System - Energy Innovation Portal Industrial Technologies Industrial Technologies Geothermal Geothermal Find More Like This Return to Search Improved Laser Induced Breakdown Spectroscopy (LIBS) Elemental Composition Detection System A device to measure subsurface gases, liquids, and solids at subsurface conditions National Energy Technology Laboratory Contact NETL About This Technology Technology Marketing Summary This device can measure subsurface gases, liquids, and solids at

  8. Electronic band structure and Kondo coupling in YbRh2Si2

    SciTech Connect (OSTI)

    Wigger, G.A.

    2010-04-15

    The electronic band structure of YbRh2Si2 is calculated in a relativistic framework including correlation corrections and magnetization of the Yb ion and compared to detailed angle-resolved photoemission spectra. The photoemission spectra for LuRh2Si2 are used as reference to identify electronic bands with no f symmetry. The calculated band structure manifests a 4f13 spin-polarized configuration leaving the unoccupied state at 1.4eV above the Fermi energy. At the band theory level, the 4f bands are located far below the Fermi level and the anisotropic Coulomb interaction within the 4f shell spreads the multilevel into broader 4f complexes below -2.5eV . The photoemission spectra obtained on YbRh2Si2 show a clear f -multilevel splitting into j=7/2 and 5/2 excitations. The interaction of the 4f7/2 levels close to the Fermi energy with two conduction bands shows visible hybridization gaps of 45 and 80meV, respectively. We discuss the origin of these excitations and provide an analysis according to Anderson's single-impurity model with parameters suggested by the band-structure calculation and the photoemission spectra. Both experiment and theory indicate nearly identical Fermi surfaces for LuRh2Si2 and YbRh2Si2 . The valency of Yb in YbRh2Si2 is estimated to be close to +3.

  9. Protein Characterisation by Synchrotron Radiation Circular Dichroism (SRCD) Spectroscopy

    SciTech Connect (OSTI)

    Wallace, B.

    2009-01-01

    Circular dichroism (CD) spectroscopy is a well-established technique for the study of proteins. Synchrotron radiation circular dichroism (SRCD) spectroscopy extends the utility of conventional CD spectroscopy (i.e. using laboratory-based instruments) because the high light flux from a synchrotron enables collection of data to lower wavelengths, detection of spectra with higher signal-to-noise levels and measurements in the presence of strongly absorbing non-chiral components such as salts, buffers, lipids and detergents. This review describes developments in instrumentation, methodologies and bioinformatics that have enabled new applications of the SRCD technique for the study of proteins. It includes examples of the use of SRCD spectroscopy for providing static and dynamic structural information on molecules, including determinations of secondary structures of intact proteins and domains, assessment of protein stability, detection of conformational changes associated with ligand and drug binding, monitoring of environmental effects, examination of the processes of protein folding and membrane insertion, comparisons of mutant and modified proteins, identification of intermolecular interactions and complex formation, determination of the dispositions of proteins in membranes, identification of natively disordered proteins and their binding partners and examination of the carbohydrate components of glycoproteins. It also discusses how SRCD can be used in conjunction with macromolecular crystallography and other biophysical techniques to provide a more complete picture of protein structures and functions, including how proteins interact with other macromolecules and ligands. This review also includes a discussion of potential new applications in structural and functional genomics using SRCD spectroscopy and future instrumentation and bioinformatics developments that will enable such studies. Finally, the appendix describes a number of computational/bioinformatics resources for secondary structure analyses that take advantage of the improved data quality available from SRCD. In summary, this review discusses how SRCD can be used for a wide range of structural and functional studies of proteins.

  10. Pulsed laser Raman spectroscopy in the laser-heated diamond anvil...

    Office of Scientific and Technical Information (OSTI)

    Pulsed laser Raman spectroscopy in the laser-heated diamond anvil cell Citation Details In-Document Search Title: Pulsed laser Raman spectroscopy in the laser-heated diamond anvil...

  11. Two-dimensional gas-phase coherent anti-Stokes Raman spectroscopy...

    Office of Scientific and Technical Information (OSTI)

    Two-dimensional gas-phase coherent anti-Stokes Raman spectroscopy (2D-CARS): simultaneous planar imaging and multiplex spectroscopy in a single laser shot. Citation Details...

  12. Soft X-Ray and Vacuum Ultraviolet Based Spectroscopy of the Actinides...

    Office of Scientific and Technical Information (OSTI)

    Conference: Soft X-Ray and Vacuum Ultraviolet Based Spectroscopy of the Actinides Citation Details In-Document Search Title: Soft X-Ray and Vacuum Ultraviolet Based Spectroscopy of...

  13. Hubbard model corrections in real-space x-ray spectroscopy theory...

    Office of Scientific and Technical Information (OSTI)

    Hubbard model corrections in real-space x-ray spectroscopy theory Citation Details In-Document Search Title: Hubbard model corrections in real-space x-ray spectroscopy theory...

  14. X-ray line polarization spectroscopy of Li-like satellite line...

    Office of Scientific and Technical Information (OSTI)

    Journal Article: X-ray line polarization spectroscopy of Li-like satellite line spectra Citation Details In-Document Search Title: X-ray line polarization spectroscopy of Li-like...

  15. In Operando Soft X-ray Spectroscopy of 3D Graphene Supercapacitor...

    Office of Scientific and Technical Information (OSTI)

    In Operando Soft X-ray Spectroscopy of 3D Graphene Supercapacitor Electrodes Citation Details In-Document Search Title: In Operando Soft X-ray Spectroscopy of 3D Graphene...

  16. 10 Questions for a Spectroscopy Expert: Nancy Hess | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Spectroscopy Expert: Nancy Hess 10 Questions for a Spectroscopy Expert: Nancy Hess April 14, 2011 - 4:34pm Addthis Nancy Hess | Photo Courtesy of Pacific Northwest National Lab (PNNL) Nancy Hess | Photo Courtesy of Pacific Northwest National Lab (PNNL) Niketa Kumar Niketa Kumar Public Affairs Specialist, Office of Public Affairs "I have always enjoyed the beauty and the complexity of processes in the natural world -- Spectroscopy gives you that insight." Nancy Hess, Spectroscopy Expert

  17. Ion dip spectroscopy of cold molecules and ions. Progress report and renewal proposal

    SciTech Connect (OSTI)

    Wessel, J.

    1987-08-13

    A research program is underway with the objective of developing techniques of high resolution multiphoton spectroscopy for selective, ultrasensitive molecular detection. Methods under study include various forms of ion dip spectroscopy and new methods of ion fragmentation spectroscopy. The studies are providing a new understanding of the fundamental spectroscopy and photophysics of large molecular ions. Dimer and cluster ions of polynuclear aromatics and related species are also being investigated, with potential detection applications.

  18. Microsoft PowerPoint - BackeSHE2015LaserSpectroscopy [Kompatibilitätsmodus]

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Laser Spectroscopy of Superheavy Elements Hartmut Backe 1 , Michael Block, Mustapha Laatiaoui, Werner Lauth 1 University of Mainz, Germany International Symposium Super Heavy Nuclei 2015, Texas A&M University, College Station, Texas, USA, March 31 - April 02, 2015 Outline 1. Introduction and Motivation 2. How Sensitive is Optical Spectroscopy? 3. Remarks on Laser Induced Fluorescence (LIF) Spectroscopy in a Buffer Gas Trap 4. RAdioactive Decay Detected Resonance Ionization Spectroscopy

  19. Applications of laser-induced gratings to spectroscopy and dynamics

    SciTech Connect (OSTI)

    Rohlfing, E.A.

    1993-12-01

    This program has traditionally emphasized two principal areas of research. The first is the spectroscopic characterization of large-amplitude motion on the ground-state potential surface of small, transient molecules. The second is the reactivity of carbonaceous clusters and its relevance to soot and fullerene formation in combustion. Motivated initially by the desire to find improved methods of obtaining stimulated emission pumping (SEP) spectra of transients, most of our recent work has centered on the use of laser-induced gratings or resonant four-wave mixing in free-jet expansions. These techniques show great promise for several chemical applications, including molecular spectroscopy and photodissociation dynamics. The author describes recent applications of two-color laser-induced grating spectroscopy (LIGS) to obtain background-free SEP spectra of transients and double resonance spectra of nonfluorescing species, and the use of photofragment transient gratings to probe photodissociation dynamics.

  20. Cone penetrometer fiber optic raman spectroscopy probe assembly

    DOE Patents [OSTI]

    Kyle, Kevin R. (Brentwood, CA); Brown, Steven B. (Livermore, CA)

    2000-01-01

    A chemically and mechanically robust optical Raman spectroscopy probe assembly that can be incorporated in a cone penetrometer (CPT) for subsurface deployment. This assembly consists of an optical Raman probe and a penetrometer compatible optical probe housing. The probe is intended for in-situ chemical analysis of chemical constituents in the surrounding environment. The probe is optically linked via fiber optics to the light source and the detection system at the surface. A built-in broadband light source provides a strobe method for direct measurement of sample optical density. A mechanically stable sapphire window is sealed directly into the side-wall of the housing using a metallic, chemically resistant, hermetic seal design. This window permits transmission of the interrogation light beam and the resultant signal. The spectroscopy probe assembly is capable of accepting Raman, Laser induced Fluorescence, reflectance, and other optical probes with collimated output for CPT deployment.

  1. Real-time multiplexed digital cavity-enhanced spectroscopy

    SciTech Connect (OSTI)

    Boyson, Toby K.; Dagdigian, Paul J.; Pavey, Karl D.; Fitzgerald, Nicholas J.; Spence, Thomas G.; Moore, David S.; Harb, Charles C.

    2015-10-01

    Cavity-enhanced spectroscopy is a sensitive optical absorption technique but one where the practical applications have been limited to studying small wavelength ranges. In addition, this Letter shows that wideband operation can be achieved by combining techniques usually reserved for the communications community with that of cavity-enhanced spectroscopy, producing a multiplexed real-time cavity-enhanced spectrometer. We use multiple collinear laser sources operating asynchronously and simultaneously while being detected on a single photodetector. This is synonymous with radio frequency (RF) cellular systems in which signals are detected on a single antenna but decoded uniquely. Here, we demonstrate results with spectra of methyl salicylate and show parts-per-billion per root hertz sensitivity measured in real-time.

  2. Method and apparatus for two-dimensional spectroscopy

    DOE Patents [OSTI]

    DeCamp, Matthew F. (Swarthmore, PA); Tokmakoff, Andrei (Lexington, MA)

    2010-10-12

    Preferred embodiments of the invention provide for methods and systems of 2D spectroscopy using ultrafast, first light and second light beams and a CCD array detector. A cylindrically-focused second light beam interrogates a target that is optically interactive with a frequency-dispersed excitation (first light) pulse, whereupon the second light beam is frequency-dispersed at right angle orientation to its line of focus, so that the horizontal dimension encodes the spatial location of the second light pulse and the first light frequency, while the vertical dimension encodes the second light frequency. Differential spectra of the first and second light pulses result in a 2D frequency-frequency surface equivalent to double-resonance spectroscopy. Because the first light frequency is spatially encoded in the sample, an entire surface can be acquired in a single interaction of the first and second light pulses.

  3. Single-electron detection and spectroscopy via relativistic cyclotron radiation

    SciTech Connect (OSTI)

    Asner, David M.; Bradley, Rich; De Viveiros Souza Filho, Luiz A.; Doe, Peter J.; Fernandes, Justin L.; Fertl, M.; Finn, Erin C.; Formaggio, Joseph; Furse, Daniel L.; Jones, Anthony M.; Kofron, Jared N.; LaRoque, Benjamin; Leber, Michelle; MCBride, Lisa; Miller, M. L.; Mohanmurthy, Prajwal T.; Monreal, Ben; Oblath, Noah S.; Robertson, R. G. H.; Rosenberg, Leslie; Rybka, Gray; Rysewyk, Devyn M.; Sternberg, Michael G.; Tedeschi, Jonathan R.; Thummler, Thomas; VanDevender, Brent A.; Woods, N. L.

    2015-04-01

    It has been understood since 1897 that accelerating charges should emit electromagnetic radiation. Cyclotron radiation, the particular form of radiation emitted by an electron orbiting in a magnetic field, was first derived in 1904. Despite the simplicity of this concept, and the enormous utility of electron spectroscopy in nuclear and particle physics, single-electron cyclotron radiation has never been observed directly. Here we demonstrate single-electron detection in a novel radiofrequency spectrometer. We observe the cyclotron radiation emitted by individual electrons that are produced with mildly-relativistic energies by a gaseous radioactive source and are magnetically trapped. The relativistic shift in the cyclotron frequency permits a precise electron energy measurement. Precise beta electron spectroscopy from gaseous radiation sources is a key technique in modern efforts to measure the neutrino mass via the tritium decay endpoint, and this work is a proof-of-concept for future neutrino mass experiments using this technique.

  4. Real-time multiplexed digital cavity-enhanced spectroscopy

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Boyson, Toby K.; Dagdigian, Paul J.; Pavey, Karl D.; Fitzgerald, Nicholas J.; Spence, Thomas G.; Moore, David S.; Harb, Charles C.

    2015-10-01

    Cavity-enhanced spectroscopy is a sensitive optical absorption technique but one where the practical applications have been limited to studying small wavelength ranges. In addition, this Letter shows that wideband operation can be achieved by combining techniques usually reserved for the communications community with that of cavity-enhanced spectroscopy, producing a multiplexed real-time cavity-enhanced spectrometer. We use multiple collinear laser sources operating asynchronously and simultaneously while being detected on a single photodetector. This is synonymous with radio frequency (RF) cellular systems in which signals are detected on a single antenna but decoded uniquely. Here, we demonstrate results with spectra of methyl salicylatemore » and show parts-per-billion per root hertz sensitivity measured in real-time.« less

  5. Probing battery chemistry with liquid cell electron energy loss spectroscopy

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Unocic, Raymond R.; Baggetto, Loic; Veith, Gabriel M.; Unocic, Kinga A.; Sacci, Robert L.; Dudney, Nancy J.; More, Karren Leslie; Aguiar, Jeffery A.

    2015-09-15

    Electron energy loss spectroscopy (EELS) was used to determine the chemistry and oxidation state of LiMn2O4 and Li4Ti5O12 thin film battery electrodes in liquid cells for in situ scanning/transmission electron microscopy (S/TEM). Using the L2,3 white line intensity ratio method we determine the oxidation state of Mn and Ti in a liquid electrolyte solvent and discuss experimental parameters that influence measurement sensitivity.

  6. Ramsey-type spectroscopy in the XUV spectral region

    SciTech Connect (OSTI)

    Pirri, A. [IFAC-CNR, Via Madonna del piano 10, 50019 Sesto Fiorentino (Italy); European Laboratory for Nonlinear Spectroscopy, Via N. Carrara 1, I-50019 Sesto Fiorentino (Italy); Sali, E.; Cavalieri, S. [Dipartimento di Fisica, Universita di Firenze, Via G. Sansone 1, I-50019 Sesto Fiorentino (Italy); European Laboratory for Nonlinear Spectroscopy, Via N. Carrara 1, I-50019 Sesto Fiorentino (Italy); Corsi, C. [European Laboratory for Nonlinear Spectroscopy, Via N. Carrara 1, I-50019 Sesto Fiorentino (Italy); Bellini, M. [Istituto Nazionale di Ottica Applicata (CNR), Largo E. Fermi 6, I-50125 Sesto Fiorentino (Italy); European Laboratory for Nonlinear Spectroscopy, Via N. Carrara 1, I-50019 Sesto Fiorentino (Italy); Eramo, R. [European Laboratory for Nonlinear Spectroscopy, Via N. Carrara 1, I-50019 Sesto Fiorentino (Italy); INFM-CRS-Soft Matter (CNR), Piazzale A. Moro 2, 00185 Roma (Italy)

    2010-02-02

    We report an experimental and theoretical investigation of Ramsey-type spectroscopy with high-order harmonic generation applied to autoionizing states of Krypton. The ionization yield, detected by an ion-mass spectrometer, shows the characteristic quantum interference pattern. The behaviour of the fringe contrast was interpreted on the basis of a simple analytic model, which reproduces the experimental data without any free parameter.

  7. New focusing multilayer structures for X-ray plasma spectroscopy

    SciTech Connect (OSTI)

    Bibishkin, M S; Luchin, V I; Salashchenko, N N; Chernov, V V; Chkhalo, N I; Kazakov, E D; Shevelko, A P

    2008-02-28

    New focusing short-period multilayer structures are developed which opens up wide possibilities for X-ray and VUV spectroscopy. Multilayer structures are deposited on a flat surface of a mica crystal which is then bent to a small-radius cylinder. The use of this structure in a von Hamos spectrometer for X-ray laser plasma diagnostics is demonstrated. (interaction of laser radiation with matter. laser plasma)

  8. Frequency Modulation Spectroscopy Modeling for Remote Chemical Detection

    SciTech Connect (OSTI)

    Sheen, David M.

    2000-09-30

    Frequency modulation (FM) spectroscopy techniques show promise for active infrared remote chemical sensing. FM spectroscopy techniques have reduced sensitivity to optical and electronic noise, and are relatively immune to the effects of various electronic and mechanical drifts. FM systems are responsive to sharp spectral features and can therefore reduce the effects of spectral clutter due to interfering chemicals in the plume or in the atmosphere. The relatively high modulation frequencies used for FM also reduces the effects of albedo (reflectance) and plume variations. Conventional differential absorption lidar (DIAL) systems are performance limited by the noise induced by speckle. Analysis presented in this report shows that FM based sensors may reduce the effects of speckle by one to two orders of magnitude. This can result in reduced dwell times and faster area searches, as well as reducing various forms of spatial clutter. FM systems will require a laser system that is continuously tunable at relatively high frequencies (0.1 to 20 MHz). One promising candidate is the quantum-cascade (QC) laser [1, 2]. The QC laser is potentially capable of power levels on the order of 1 Watt and frequency tuning on the order of 3 - 6 GHz, which is the performance level required for FM spectroscopy based remote sensing. In this report we describe a high-level numerical model for an FM spectroscopy based remote sensing system, and application to two unmanned airborne vehicle (UAV) scenarios. A Predator scenario operating at a slant range of 6.5 km with a 10 cm diameter telescope, and a Global Hawk scenario operating at a range of 30 km with a 20 cm diameter telescope, has been assumed to allow estimation of the performance of potential FM systems.

  9. Detection of lateral composition modulation by magnetoexciton spectroscopy

    SciTech Connect (OSTI)

    Jones, E.D.; Millunchick, J.M.; Follstaedt, D.; Lee, S.; Reno, J.; Twesten, R.D.; Zhang, Y.; Mascerenhas, A.

    1997-07-10

    An experimental signature for detecting spontaneous lateral composition modulation in a (InAs){sub n}/(GaAs){sub m} short period superlattice on an InP substrate based on magnetoexciton spectroscopy described. The authors find by aligning the magnetic field in three crystallographic directions, one parallel to and the other two perpendicular to the composition modulation direction, that the magnetoexciton shifts are anisotropic and are a good indicator for the presence of composition modulation.

  10. Observing Interactions as they happen: Ultrafast Optical Spectroscopies of

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Quantum Materials | Stanford Synchrotron Radiation Lightsource Observing Interactions as they happen: Ultrafast Optical Spectroscopies of Quantum Materials Wednesday, January 13, 2016 - 3:00pm SLAC, Redtail Hawk Conference Room 108A Speaker: Giacomo Coslovich, LCLS Program Description Quantum materials exhibit strong and competing interactions between their fundamental constituents, leading to exotic properties such as high-temperature superconductivity and nanoscale charge and spin

  11. Dirac Charge Dynamcs in Graphene by Infrared Spectroscopy

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Dirac Charge Dynamcs in Graphene by Infrared Spectroscopy Print Graphene-a single layer of carbon atoms arranged in a honeycomb lattice-has very high conductivity that can be tuned by applying a gate voltage. The charge carriers in graphene can travel ballistically over great distances (~1 micron) without scattering. These unusual electronic properties make graphene a promising candidate for future nanoelectronics. Using infrared spectromicroscopy at ALS Beamline 1.4, a group of researchers from

  12. Dirac Charge Dynamcs in Graphene by Infrared Spectroscopy

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Dirac Charge Dynamcs in Graphene by Infrared Spectroscopy Print Graphene-a single layer of carbon atoms arranged in a honeycomb lattice-has very high conductivity that can be tuned by applying a gate voltage. The charge carriers in graphene can travel ballistically over great distances (~1 micron) without scattering. These unusual electronic properties make graphene a promising candidate for future nanoelectronics. Using infrared spectromicroscopy at ALS Beamline 1.4, a group of researchers from

  13. Dirac Charge Dynamcs in Graphene by Infrared Spectroscopy

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Dirac Charge Dynamcs in Graphene by Infrared Spectroscopy Print Graphene-a single layer of carbon atoms arranged in a honeycomb lattice-has very high conductivity that can be tuned by applying a gate voltage. The charge carriers in graphene can travel ballistically over great distances (~1 micron) without scattering. These unusual electronic properties make graphene a promising candidate for future nanoelectronics. Using infrared spectromicroscopy at ALS Beamline 1.4, a group of researchers from

  14. Dirac Charge Dynamcs in Graphene by Infrared Spectroscopy

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Dirac Charge Dynamcs in Graphene by Infrared Spectroscopy Print Graphene-a single layer of carbon atoms arranged in a honeycomb lattice-has very high conductivity that can be tuned by applying a gate voltage. The charge carriers in graphene can travel ballistically over great distances (~1 micron) without scattering. These unusual electronic properties make graphene a promising candidate for future nanoelectronics. Using infrared spectromicroscopy at ALS Beamline 1.4, a group of researchers from

  15. Dirac Charge Dynamcs in Graphene by Infrared Spectroscopy

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Dirac Charge Dynamcs in Graphene by Infrared Spectroscopy Print Graphene-a single layer of carbon atoms arranged in a honeycomb lattice-has very high conductivity that can be tuned by applying a gate voltage. The charge carriers in graphene can travel ballistically over great distances (~1 micron) without scattering. These unusual electronic properties make graphene a promising candidate for future nanoelectronics. Using infrared spectromicroscopy at ALS Beamline 1.4, a group of researchers from

  16. Dirac Charge Dynamcs in Graphene by Infrared Spectroscopy

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Dirac Charge Dynamcs in Graphene by Infrared Spectroscopy Print Graphene-a single layer of carbon atoms arranged in a honeycomb lattice-has very high conductivity that can be tuned by applying a gate voltage. The charge carriers in graphene can travel ballistically over great distances (~1 micron) without scattering. These unusual electronic properties make graphene a promising candidate for future nanoelectronics. Using infrared spectromicroscopy at ALS Beamline 1.4, a group of researchers from

  17. Dirac Charge Dynamcs in Graphene by Infrared Spectroscopy

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Dirac Charge Dynamcs in Graphene by Infrared Spectroscopy Print Graphene-a single layer of carbon atoms arranged in a honeycomb lattice-has very high conductivity that can be tuned by applying a gate voltage. The charge carriers in graphene can travel ballistically over great distances (~1 micron) without scattering. These unusual electronic properties make graphene a promising candidate for future nanoelectronics. Using infrared spectromicroscopy at ALS Beamline 1.4, a group of researchers from

  18. Nonlinearity sensing via photon-statistics excitation spectroscopy

    SciTech Connect (OSTI)

    Assmann, Marc; Bayer, Manfred

    2011-11-15

    We propose photon-statistics excitation spectroscopy as an adequate tool to describe the optical response of a nonlinear system. To this end we suggest to use optical excitation with varying photon statistics as another spectroscopic degree of freedom to gather information about the system in question. The responses of several simple model systems to excitation beams with different photon statistics are discussed. Possible spectroscopic applications in terms of identifying lasing operation are pointed out.

  19. Laser-induced breakdown spectroscopy for specimen analysis

    DOE Patents [OSTI]

    Kumar, Akshaya; Yu-Yueh, Fang; Burgess, Shane C.; Singh, Jagdish P.

    2006-08-15

    The present invention is directed to an apparatus, a system and a method for detecting the presence or absence of trace elements in a biological sample using Laser-Induced Breakdown Spectroscopy. The trace elements are used to develop a signature profile which is analyzed directly or compared with the known profile of a standard. In one aspect of the invention, the apparatus, system and method are used to detect malignant cancer cells in vivo.

  20. Laser produced plasma diagnostics by cavity ringdown spectroscopy and applications

    SciTech Connect (OSTI)

    Milosevic, S.

    2012-05-25

    Laser-produced plasmas have many applications for which detailed characterization of the plume is requested. Cavity ring-down spectroscopy is a versatile absorption method which provides data on the plume and its surroundings, with spatial and temporal resolution. The measured absorption line shapes contain information about angular and velocity distributions within the plume. In various plasmas we have observed molecules or metastable atoms which were not present in the emission spectra.

  1. Quarkonium Spectroscopy and New States from BaBar

    SciTech Connect (OSTI)

    Vitale, L.; /Trieste U. /INFN, Trieste

    2007-06-08

    We review results on charmonium and bottomonium spectroscopy by the BaBar experiment at the PEP-II e{sup +}e{sup -} collider at SLAC. More space is reserved to the new results like the observation of hadronic non-B{bar B} {Upsilon}(4S) decays and the investigation on the production and decay properties of the recently discovered charmonium-like states X(3872) and Y (4260). These results are preliminary, unless otherwise specified.

  2. Low-loss electron energy loss spectroscopy: An atomic-resolution complement to optical spectroscopies and application to graphene

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Kapetanakis, Myron; Zhou, Wu; Oxley, Mark P.; Lee, Jaekwang; Prange, Micah P.; Pennycook, Stephen J.; Idrobo Tapia, Juan Carlos; Pantelides, Sokrates T.

    2015-09-25

    Photon-based spectroscopies have played a central role in exploring the electronic properties of crystalline solids and thin films. They are a powerful tool for probing the electronic properties of nanostructures, but they are limited by lack of spatial resolution. On the other hand, electron-based spectroscopies, e.g., electron energy loss spectroscopy (EELS), are now capable of subangstrom spatial resolution. Core-loss EELS, a spatially resolved analog of x-ray absorption, has been used extensively in the study of inhomogeneous complex systems. In this paper, we demonstrate that low-loss EELS in an aberration-corrected scanning transmission electron microscope, which probes low-energy excitations, combined with amore » theoretical framework for simulating and analyzing the spectra, is a powerful tool to probe low-energy electron excitations with atomic-scale resolution. The theoretical component of the method combines density functional theory–based calculations of the excitations with dynamical scattering theory for the electron beam. We apply the method to monolayer graphene in order to demonstrate that atomic-scale contrast is inherent in low-loss EELS even in a perfectly periodic structure. The method is a complement to optical spectroscopy as it probes transitions entailing momentum transfer. The theoretical analysis identifies the spatial and orbital origins of excitations, holding the promise of ultimately becoming a powerful probe of the structure and electronic properties of individual point and extended defects in both crystals and inhomogeneous complex nanostructures. The method can be extended to probe magnetic and vibrational properties with atomic resolution.« less

  3. Low-loss electron energy loss spectroscopy: An atomic-resolution complement to optical spectroscopies and application to graphene

    SciTech Connect (OSTI)

    Kapetanakis, Myron; Zhou, Wu; Oxley, Mark P.; Lee, Jaekwang; Prange, Micah P.; Pennycook, Stephen J.; Idrobo Tapia, Juan Carlos; Pantelides, Sokrates T.

    2015-09-25

    Photon-based spectroscopies have played a central role in exploring the electronic properties of crystalline solids and thin films. They are a powerful tool for probing the electronic properties of nanostructures, but they are limited by lack of spatial resolution. On the other hand, electron-based spectroscopies, e.g., electron energy loss spectroscopy (EELS), are now capable of subangstrom spatial resolution. Core-loss EELS, a spatially resolved analog of x-ray absorption, has been used extensively in the study of inhomogeneous complex systems. In this paper, we demonstrate that low-loss EELS in an aberration-corrected scanning transmission electron microscope, which probes low-energy excitations, combined with a theoretical framework for simulating and analyzing the spectra, is a powerful tool to probe low-energy electron excitations with atomic-scale resolution. The theoretical component of the method combines density functional theorybased calculations of the excitations with dynamical scattering theory for the electron beam. We apply the method to monolayer graphene in order to demonstrate that atomic-scale contrast is inherent in low-loss EELS even in a perfectly periodic structure. The method is a complement to optical spectroscopy as it probes transitions entailing momentum transfer. The theoretical analysis identifies the spatial and orbital origins of excitations, holding the promise of ultimately becoming a powerful probe of the structure and electronic properties of individual point and extended defects in both crystals and inhomogeneous complex nanostructures. The method can be extended to probe magnetic and vibrational properties with atomic resolution.

  4. Beamline 11.0.2

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    11.0.2 Print Molecular Environmental Science (MES) Scientific disciplines: Surface chemistry, environmental, planetary, biological, and medical sciences Endstations: Ambient-pressure photoemission spectroscopy Scanning transmission x-ray microscope (STXM) GENERAL BEAMLINE INFORMATION Operational Yes Source characteristics 5.0-cm period elliptical polarization undulator (EPU5) Energy range See endstation tables Monochromator See endstation tables Endstations Ambient-pressure photoemission

  5. Beamline 11.0.2

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    11.0.2 Print Molecular Environmental Science (MES) Scientific disciplines: Surface chemistry, environmental, planetary, biological, and medical sciences Endstations: Ambient-pressure photoemission spectroscopy Scanning transmission x-ray microscope (STXM) GENERAL BEAMLINE INFORMATION Operational Yes Source characteristics 5.0-cm period elliptical polarization undulator (EPU5) Energy range See endstation tables Monochromator See endstation tables Endstations Ambient-pressure photoemission

  6. Beamline 11.0.2

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    0.2 Print Molecular Environmental Science (MES) Scientific disciplines: Surface chemistry, environmental, planetary, biological, and medical sciences Endstations: Ambient-pressure photoemission spectroscopy Scanning transmission x-ray microscope (STXM) GENERAL BEAMLINE INFORMATION Operational Yes Source characteristics 5.0-cm period elliptical polarization undulator (EPU5) Energy range See endstation tables Monochromator See endstation tables Endstations Ambient-pressure photoemission

  7. Beamline 11.0.2

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    1.0.2 Print Molecular Environmental Science (MES) Scientific disciplines: Surface chemistry, environmental, planetary, biological, and medical sciences Endstations: Ambient-pressure photoemission spectroscopy Scanning transmission x-ray microscope (STXM) GENERAL BEAMLINE INFORMATION Operational Yes Source characteristics 5.0-cm period elliptical polarization undulator (EPU5) Energy range See endstation tables Monochromator See endstation tables Endstations Ambient-pressure photoemission

  8. Beamline 11.0.2

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    1.0.2 Print Molecular Environmental Science (MES) Scientific disciplines: Surface chemistry, environmental, planetary, biological, and medical sciences Endstations: Ambient-pressure photoemission spectroscopy Scanning transmission x-ray microscope (STXM) GENERAL BEAMLINE INFORMATION Operational Yes Source characteristics 5.0-cm period elliptical polarization undulator (EPU5) Energy range See endstation tables Monochromator See endstation tables Endstations Ambient-pressure photoemission

  9. Electronic structure of Co-Ni-Ga Heusler alloys studied by resonant

    Office of Scientific and Technical Information (OSTI)

    photoemission (Journal Article) | SciTech Connect Electronic structure of Co-Ni-Ga Heusler alloys studied by resonant photoemission Citation Details In-Document Search Title: Electronic structure of Co-Ni-Ga Heusler alloys studied by resonant photoemission The electronic structures of Co{sub 2.01}Ni{sub 1.05}Ga{sub 0.94} and Co{sub 1.76}Ni{sub 1.46}Ga{sub 0.78} Heusler alloys have been investigated by resonant photoemission spectroscopy across the 3p-3d transition of Co and Ni. For the Ni

  10. Twist Solves Bilayer Graphene Mystery

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Twist Solves Bilayer Graphene Mystery Print Researchers have discovered a unique new twist to the story of graphene and, in the process, appear to have solved a mystery that has held back device development. Working at ALS Beamline 7.0.1, a research team applied angle-resolved photoelectron spectroscopy (ARPES) to bilayer graphene. Through direct band-structure measurements and calculations, they discovered that in the stacking of graphene monolayers, subtle misalignments arise, creating an

  11. Twist Solves Bilayer Graphene Mystery

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Twist Solves Bilayer Graphene Mystery Print Researchers have discovered a unique new twist to the story of graphene and, in the process, appear to have solved a mystery that has held back device development. Working at ALS Beamline 7.0.1, a research team applied angle-resolved photoelectron spectroscopy (ARPES) to bilayer graphene. Through direct band-structure measurements and calculations, they discovered that in the stacking of graphene monolayers, subtle misalignments arise, creating an

  12. Twist Solves Bilayer Graphene Mystery

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Twist Solves Bilayer Graphene Mystery Twist Solves Bilayer Graphene Mystery Print Wednesday, 26 March 2014 00:00 Researchers have discovered a unique new twist to the story of graphene and, in the process, appear to have solved a mystery that has held back device development. Working at ALS Beamline 7.0.1, a research team applied angle-resolved photoelectron spectroscopy (ARPES) to bilayer graphene. Through direct band-structure measurements and calculations, they discovered that in the stacking

  13. Twist Solves Bilayer Graphene Mystery

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Twist Solves Bilayer Graphene Mystery Print Researchers have discovered a unique new twist to the story of graphene and, in the process, appear to have solved a mystery that has held back device development. Working at ALS Beamline 7.0.1, a research team applied angle-resolved photoelectron spectroscopy (ARPES) to bilayer graphene. Through direct band-structure measurements and calculations, they discovered that in the stacking of graphene monolayers, subtle misalignments arise, creating an

  14. Twist Solves Bilayer Graphene Mystery

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Twist Solves Bilayer Graphene Mystery Print Researchers have discovered a unique new twist to the story of graphene and, in the process, appear to have solved a mystery that has held back device development. Working at ALS Beamline 7.0.1, a research team applied angle-resolved photoelectron spectroscopy (ARPES) to bilayer graphene. Through direct band-structure measurements and calculations, they discovered that in the stacking of graphene monolayers, subtle misalignments arise, creating an

  15. The Meson Spectroscopy Program at the Jefferson Laboratory

    SciTech Connect (OSTI)

    Filippi, Alessandro

    2015-06-01

    The experimental techniques that will be applied by the next generation meson spectroscopy experiments at JLab are described. For the first time, these experiments will be able to exploit the features of a photon beam of unprecedented intensity and momentum resolution, that will allow to perform precision studies of meson states with masses below 3 GeV/c2. Photon induced reactions will enhance the production of spin-1 mesons, that are of particular interest according to the most recent Lattice QCD calculations of the lightest exotic hybrid meson.

  16. Molecular shock response of explosives: electronic absorption spectroscopy

    SciTech Connect (OSTI)

    Mcgrne, Shawn D; Moore, David S; Whitley, Von H; Bolme, Cindy A; Eakins, Daniel E

    2009-01-01

    Electronic absorption spectroscopy in the range 400-800 nm was coupled to ultrafast laser generated shocks to begin addressing the question of the extent to which electronic excitations are involved in shock induced reactions. Data are presented on shocked polymethylmethacrylate (PMMA) thin films and single crystal pentaerythritol tetranitrate (PETN). Shocked PMMA exhibited thin film interference effects from the shock front. Shocked PETN exhibited interference from the shock front as well as broadband increased absorption. Relation to shock initiation hypotheses and the need for time dependent absorption data (future experiments) is briefly discussed.

  17. Holdup Measures on an SRNL Mossbauer Spectroscopy Instrument

    SciTech Connect (OSTI)

    Dewberry, R.; Brown, T.; Salaymeh, S.

    2010-05-05

    Gamma-ray holdup measurements of a Mossbauer spectroscopy instrument are described and modeled. In the qualitative acquisitions obtained in a low background area of Savannah River National Laboratory, only Am-241 and Np-237 activity were observed. The Am-241 was known to be the instrumental activation source, while the Np-237 is clearly observed as a source of contamination internal to the instrument. The two sources of activity are modeled separately in two acquisition configurations using two separate modeling tools. The results agree well, demonstrating a content of (1980 {+-} 150) {mu}Ci Am-241 and (110 {+-} 50) {mu}Ci of Np-237.

  18. Probing Battery Chemistry with Liquid Cell Electron Energy Loss Spectroscopy

    SciTech Connect (OSTI)

    Unocic, Raymond R.; Baggetto, Loic; Veith, Gabriel M.; Aguiar, Jeffery A.; Unocic, Kinga A.; Sacci, Robert L.; Dudney, Nancy J.; More, Karren L.

    2015-11-25

    We demonstrate the ability to apply electron energy loss spectroscopy (EELS) to follow the chemistry and oxidation states of LiMn2O4 and Li4Ti5O12 battery electrodes within a battery solvent. The use and importance of in situ electrochemical cells coupled with a scanning/transmission electron microscope (S/TEM) has expanded and been applied to follow changes in battery chemistry during electrochemical cycling. Furthermore, we discuss experimental parameters that influence measurement sensitivity and provide a framework to apply this important analytical method to future in situ electrochemical studies.

  19. Elastic properties of gamma-Pu by resonant ultrasound spectroscopy

    SciTech Connect (OSTI)

    Migliori, Albert; Betts, J; Trugman, A; Mielke, C H; Mitchell, J N; Ramos, M; Stroe, I

    2009-01-01

    Despite intense experimental and theoretical work on Pu, there is still little understanding of the strange properties of this metal. We used resonant ultrasound spectroscopy method to investigate the elastic properties of pure polycrystalline Pu at high temperatures. Shear and longitudinal elastic moduli of the {gamma}-phase of Pu were determined simultaneously and the bulk modulus was computed from them. A smooth linear and large decrease of all elastic moduli with increasing temperature was observed. We calculated the Poisson ratio and found that it increases from 0.242 at 519K to 0.252 at 571K.

  20. Terahertz spectroscopy of two-dimensional subwavelength plasmonic structures

    SciTech Connect (OSTI)

    Azad, Abul K; Chen, Houtong; Taylor, Antoinette; O' Hara, John F; Han, Jiaguang; Lu, Xinchao; Zhang, Weili

    2009-01-01

    The fascinating properties of plasmonic structures have had significant impact on the development of next generation ultracompact photonic and optoelectronic components. We study two-dimensional plasmonic structures functioning at terahertz frequencies. Resonant terahertz response due to surface plasmons and dipole localized surface plasmons were investigated by the state-of-the-art terahertz time domain spectroscopy (THz-TDS) using both transmission and reflection configurations. Extraordinary terahertz transmission was demonstrated through the subwavelength metallic hole arrays made from good conducting metals as well as poor metals. Metallic arrays m!lde from Pb, generally a poor metal, and having optically thin thicknesses less than one-third of a skin depth also contributed in enhanced THz transmission. A direct transition of a surface plasmon resonance from a photonic crystal minimum was observed in a photo-doped semiconductor array. Electrical controls of the surface plasmon resonances by hybridization of the Schottkey diode between the metallic grating and the semiconductor substrate are investigated as a function of the applied reverse bias. In addition, we have demonstrated photo-induced creation and annihilation of surface plasmons with appropriate semiconductors at room temperature. According to the Fano model, the transmission properties are characterized by two essential contributions: resonant excitation of surface plasmons and nonresonant direct transmission. Such plasmonic structures may find fascinating applications in terahertz imaging, biomedical sensing, subwavelength terahertz spectroscopy, tunable filters, and integrated terahertz devices.

  1. Soft-x-ray spectroscopy study of nanoscale materials

    SciTech Connect (OSTI)

    Guo, J.-H.

    2005-07-30

    The ability to control the particle size and morphology of nanoparticles is of crucial importance nowadays both from a fundamental and industrial point of view considering the tremendous amount of high-tech applications. Controlling the crystallographic structure and the arrangement of atoms along the surface of nanostructured material will determine most of its physical properties. In general, electronic structure ultimately determines the properties of matter. Soft X-ray spectroscopy has some basic features that are important to consider. X-ray is originating from an electronic transition between a localized core state and a valence state. As a core state is involved, elemental selectivity is obtained because the core levels of different elements are well separated in energy, meaning that the involvement of the inner level makes this probe localized to one specific atomic site around which the electronic structure is reflected as a partial density-of-states contribution. The participation of valence electrons gives the method chemical state sensitivity and further, the dipole nature of the transitions gives particular symmetry information. The new generation synchrotron radiation sources producing intensive tunable monochromatized soft X-ray beams have opened up new possibilities for soft X-ray spectroscopy. The introduction of selectively excited soft X-ray emission has opened a new field of study by disclosing many new possibilities of soft X-ray resonant inelastic scattering. In this paper, some recent findings regarding soft X-ray absorption and emission studies of various nanostructured systems are presented.

  2. Laser absorption spectroscopy system for vaporization process characterization and control

    SciTech Connect (OSTI)

    Galkowski, J.; Hagans, K.

    1993-09-07

    In support of the Lawrence Livermore National Laboratory`s (LLNL`s) Uranium Atomic Vapor Laser Isotope Separation (U-AVLIS) Program, a laser atomic absorption spectroscopy (LAS) system has been developed. This multi-laser system is capable of simultaneously measuring the line densities of {sup 238}U ground and metastable states, {sup 235}U ground and metastable states, iron, and ions at up to nine locations within the separator vessel. Supporting enrichment experiments that last over one hundred hours, this laser spectroscopy system is employed to diagnose and optimize separator system performance, control the electron beam vaporizer and metal feed systems, and provide physics data for the validation of computer models. As a tool for spectroscopic research, vapor plume characterization, vapor deposition monitoring, and vaporizer development, LLNL`s LAS laboratory with its six argon-ion-pumped ring dye lasers and recently added Ti:Sapphire and external-cavity diode-lasers has capabilities far beyond the requirements of its primary mission.

  3. X-ray imaging crystal spectroscopy for use in plasma transport research

    Office of Scientific and Technical Information (OSTI)

    (Journal Article) | SciTech Connect X-ray imaging crystal spectroscopy for use in plasma transport research Citation Details In-Document Search Title: X-ray imaging crystal spectroscopy for use in plasma transport research This research describes advancements in the spectral analysis and error propagation techniques associated with x-ray imaging crystal spectroscopy (XICS) that have enabled this diagnostic to be used to accurately constrain particle, momentum, and heat transport studies in a

  4. The X-ray correlation spectroscopy instrument at the Linac Coherent...

    Office of Scientific and Technical Information (OSTI)

    spectroscopy. Double-pulse schemes could probe dynamics on the picosecond timescale. In addition, a description of the instrument capabilities and recent achievements is...

  5. A new spectrometer design for the x-ray spectroscopy of laser...

    Office of Scientific and Technical Information (OSTI)

    A new spectrometer design for the x-ray spectroscopy of laser-produced plasmas with high ... Author Affiliations Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 ...

  6. Scanning angle Raman spectroscopy: Investigation of Raman scatter enhancement techniques for chemical analysis

    SciTech Connect (OSTI)

    Meyer, Matthew W.

    2013-03-14

    This thesis outlines advancements in Raman scatter enhancement techniques by applying evanescent fields, standing-waves (waveguides) and surface enhancements to increase the generated mean square electric field, which is directly related to the intensity of Raman scattering. These techniques are accomplished by employing scanning angle Raman spectroscopy and surface enhanced Raman spectroscopy. A 1064 nm multichannel Raman spectrometer is discussed for chemical analysis of lignin. Extending dispersive multichannel Raman spectroscopy to 1064 nm reduces the fluorescence interference that can mask the weaker Raman scattering. Overall, these techniques help address the major obstacles in Raman spectroscopy for chemical analysis, which include the inherently weak Raman cross section and susceptibility to fluorescence interference.

  7. 31P-Edited Diffusion-Ordered 1H NMR Spectroscopy for the Isolation...

    Office of Scientific and Technical Information (OSTI)

    31P-Edited Diffusion-Ordered 1H NMR Spectroscopy for the Isolation and Identification of Organophosphorus Compounds Related to Chemical Weapons Agents and their Degradation...

  8. A photoemission study of Pd ultrathin films on Pt(111)

    SciTech Connect (OSTI)

    Mun, Bongjin Simon; Lee, Choongman; Stamenkovic, Vojislav; Markovic, Nenad M.; Ross Jr., Philip N.

    2005-05-11

    The origin of surface core-level shift (SCLS) of Pd thin films on Pt(111) substrate is investigated. At sub-monolayer coverage of Pd thin films, the splitting of Pd 3d core level peaks indicate the contribution of both initial and final-state of photo-ionization processes while there is almost no change on valence band (VB) spectra. When the coverage of Pd reaches to single monolayer, the final-state relaxation effect on the Pd 3d vanishes and only the initial-state effect, a negative SCLS, is present. Also, the VB spectrum at Pd monolayer films shows a clear band narrowing, that is the origin of the negative SCLS at monolayer coverage. As the Pd coverage is increased to more than monolayer thickness, the Pd 3d peaks start to show the surface layer contribution from second and third layers, positive SCLS, and the VB spectrum shows even narrower band width, possibly due to the formation of surface states and strained effect of Pd adlayers on top of the first pseudomorphic layer.

  9. Uncertainty in terahertz time-domain spectroscopy measurement

    SciTech Connect (OSTI)

    Withayachumnankul, Withawat; Fischer, Bernd M.; Lin Hungyen; Abbott, Derek

    2008-06-15

    Measurements of optical constants at terahertz--or T-ray--frequencies have been performed extensively using terahertz time-domain spectroscopy (THz-TDS). Spectrometers, together with physical models explaining the interaction between a sample and T-ray radiation, are progressively being developed. Nevertheless, measurement errors in the optical constants, so far, have not been systematically analyzed. This situation calls for a comprehensive analysis of measurement uncertainty in THz-TDS systems. The sources of error existing in a terahertz spectrometer and throughout the parameter estimation process are identified. The analysis herein quantifies the impact of each source on the output optical constants. The resulting analytical model is evaluated against experimental THz-TDS data.

  10. Single-chip detector for electron spin resonance spectroscopy

    SciTech Connect (OSTI)

    Yalcin, T.; Boero, G.

    2008-09-15

    We have realized an innovative integrated detector for electron spin resonance spectroscopy. The microsystem, consisting of an LC oscillator, a mixer, and a frequency division module, is integrated onto a single silicon chip using a conventional complementary metal-oxide-semiconductor technology. The implemented detection method is based on the measurement of the variation of the frequency of the integrated LC oscillator as a function of the applied static magnetic field, caused by the presence of a resonating sample placed over the inductor of the LC-tank circuit. The achieved room temperature spin sensitivity is about 10{sup 10} spins/GHz{sup 1/2} with a sensitive volume of about (100 {mu}m){sup 3}.

  11. Reactor cell assembly for use in spectroscopy and microscopy applications

    DOE Patents [OSTI]

    Grindstaff, Quirinus; Stowe, Ashley Clinton; Smyrl, Norm; Powell, Louis; McLane, Sam

    2015-08-04

    The present disclosure provides a reactor cell assembly that utilizes a novel design and that is wholly or partially manufactured from Aluminum, such that reactions involving Hydrogen, for example, including solid-gas reactions and thermal decomposition reactions, are not affected by any degree of Hydrogen outgassing. This reactor cell assembly can be utilized in a wide range of optical and laser spectroscopy applications, as well as optical microscopy applications, including high-temperature and high-pressure applications. The result is that the elucidation of the role of Hydrogen in the reactions studied can be achieved. Various window assemblies can be utilized, such that high temperatures and high pressures can be accommodated and the signals obtained can be optimized.

  12. Apparatus, system, and method for laser-induced breakdown spectroscopy

    DOE Patents [OSTI]

    Effenberger, Jr., Andrew J; Scott, Jill R; McJunkin, Timothy R

    2014-11-18

    In laser-induced breakdown spectroscopy (LIBS), an apparatus includes a pulsed laser configured to generate a pulsed laser signal toward a sample, a constructive interference object and an optical element, each located in a path of light from the sample. The constructive interference object is configured to generate constructive interference patterns of the light. The optical element is configured to disperse the light. A LIBS system includes a first and a second optical element, and a data acquisition module. The data acquisition module is configured to determine an isotope measurement based, at least in part, on light received by an image sensor from the first and second optical elements. A method for performing LIBS includes generating a pulsed laser on a sample to generate light from a plasma, generating constructive interference patterns of the light, and dispersing the light into a plurality of wavelengths.

  13. Electron energy loss spectroscopy of gold nanoparticles on graphene

    SciTech Connect (OSTI)

    DeJarnette, Drew [Microelectronics and Photonics Graduate Program, University of Arkansas, Fayetteville, Arkansas 72701 (United States); Roper, D. Keith, E-mail: dkroper@uark.edu [Microelectronics and Photonics Graduate Program, University of Arkansas, Fayetteville, Arkansas 72701 (United States); Department of Chemical Engineering, University of Arkansas, Fayetteville, Arkansas 72701 (United States)

    2014-08-07

    Plasmon excitation decay by absorption, scattering, and hot electron transfer has been distinguished from effects induced by incident photons for gold nanoparticles on graphene monolayer using electron energy loss spectroscopy (EELS). Gold nano-ellipses were evaporated onto lithographed graphene, which was transferred onto a silicon nitride transmission electron microscopy grid. Plasmon decay from lithographed nanoparticles measured with EELS was compared in the absence and presence of the graphene monolayer. Measured decay values compared favorably with estimated radiative and non-radiative contributions to decay in the absence of graphene. Graphene significantly enhanced low-energy plasmon decay, increasing mode width 38%, but did not affect higher energy plasmon or dark mode decay. This decay beyond expected radiative and non-radiative mechanisms was attributed to hot electron transfer, and had quantum efficiency of 20%, consistent with previous reports.

  14. New results in charm meson spectroscopy from FOCUS and SELEX

    SciTech Connect (OSTI)

    Cooper, Peter S.; /Fermilab

    2005-01-01

    I will review recent results in charmed meson spectroscopy from the Fermilab fixed target charm photo-production and hadro-production experiments, FOCUS and SELEX. FOCUS reports new measurements of the masses and widths of the D*{sub 2}{sup +} and D*{sub 2} mesons, evidence for D*{sub 0}{sup +} and D*{sub 0} broad states and a confirming observation of the D{sub sJ}{sup +}(2317) and other recently observed high mass D{sub sJ}{sup +} states. SELEX has recently reported evidence for a new D{sub sJ}{sup +}(2632) state in both the D{sub s}{sup +} {eta}{sup 0} and D{sup 0}K{sup +} final states.

  15. Reaction mechanism studies of unsaturated molecules using photofragment translational spectroscopy

    SciTech Connect (OSTI)

    Longfellow, C.A. |

    1996-05-01

    A number of molecules have been studied using the technique of photofragment translational spectroscopy. In Chapter One a brief introduction to the experimental technique is given. In Chapter Two the infrared multiphoton dissociation (IRMPD) of acetic acid is discussed. Carbon dioxide and methane were observed for the first time as products from dissociation under collisionless conditions. Chapter Three relates an IRMPD experiment of hexafluoropropene. The predominant channel produces CFCF{sub 3} or C{sub 2}F{sub 4} and CF{sub 2}, with the heavier species undergoing further dissociation to two CF{sub 2} fragments. In Chapter Four the ultraviolet (UV) dissociation of hexafluoropropene is investigated. Chapter Five explores the IRMPD of octafluoro-1-butene and octafluoro-2-butene.

  16. Fluorescence Correlation Spectroscopy at Micromolar Concentrations without Optical Nanoconfinement

    SciTech Connect (OSTI)

    Laurence, Ted A.; Ly, Sonny; Bourguet, Feliza; Fischer, Nicholas O.; Coleman, Matthew A.

    2014-08-14

    Fluorescence correlation spectroscopy (FCS) is an important technique for studying biochemical interactions dynamically that may be used in vitro and in cell-based studies. It is generally claimed that FCS may only be used at nM concentrations. We show that this general consensus is incorrect and that the limitation to nM concentrations is not fundamental but due to detector limits as well as laser fluctuations. With a high count rate detector system and applying laser fluctuation corrections, we demonstrate FCS measurements up to 38 ?M with the same signal-to-noise as at lower concentrations. Optical nanoconfinement approaches previously used to increase the concentration range of FCS are not necessary, and further increases above 38 ?M may be expected using detectors and detector arrays with higher saturation rates and better laser fluctuation corrections. This approach greatly widens the possibilities of dynamic measurements of biochemical interactions using FCS at physiological concentrations.

  17. High resolution gamma-ray spectroscopy at GANIL

    SciTech Connect (OSTI)

    France, G. de

    2014-11-11

    Gamma-ray spectroscopy is intensively used at GANIL to measure low lying states in exotic nuclei on the neutron-rich as well as on the neutron-deficient side of the nuclear chart. On the neutron deficient border, gamma-rays have been observed for the first time in {sup 92}Pd. The level scheme which could be established points to the role of isoscalar pairing. On the neutron rich side, the lifetime of excited states in nuclei around {sup 68}Ni have been been measured using the plunger technique. This allows us to study the evolution of collectivity in a broad range of nuclei. In 2014 GANIL will host the AGATA array for a campaign of at least 2 years. This array is based on the gamma-ray tracking technique, which allows an impressive gain in resolving power.

  18. Nondestructive millimeter wave imaging and spectroscopy using dielectric focusing probes

    SciTech Connect (OSTI)

    Hejase, Jose A.; Shane, Steven S.; Park, Kyoung Y.; Chahal, Premjeet [Terahertz Systems Laboratory (TeSLa) - Department of Electrical and Computer Engineering, Michigan State University, East Lansing, MI 48823 (United States)

    2014-02-18

    A tool for interrogating objects over a wide band of frequencies with subwavelength resolution at small standoff distances (near field region) in the transmission mode using a single source and detector measurement setup in the millimeter wave band is presented. The design utilizes optics like principles for guiding electromagnetic millimeter waves from large cross-sectional areas to considerably smaller sub-wavelength areas. While plano-convex lenses can be used to focus waves to a fine resolution, they usually require a large stand-off distance thus resulting in alignment and spacing issues. The design procedure and simulation analysis of the focusing probes are presented in this study along with experimental verification of performance and imaging and spectroscopy examples. Nondestructive evaluation will find benefit from such an apparatus including biological tissue imaging, electronic package integrity testing, composite dielectric structure evaluation for defects and microfluidic sensing.

  19. Experimental Study of Hypernuclei Electroproduction by High Precision Spectroscopy

    SciTech Connect (OSTI)

    Tomislav Seva

    2009-12-01

    Jlab experiment E01-011, carried out in 2005 in JLab Hall C, is the second generation of the hypernuclear spectroscopy experiments by the (e,e{prime}K{sup +}) reaction. The (e,e{prime}K{sup +}) reaction is complimentary to the associated production reactions (K{sup -},{pi}{sup -}), ({pi}{sup +},K{sup +}) since, due to a larger momentum transfer to a hyperon, excitations of both spin-non-flip and spin-flip states are possible. The experiment uses high quality and continuous primary electron beam to produce neutron rich hypernuclei on various targets by the electroproduction. The experimental setup consists of splitter magnet, high resolution kaon spectrometer (HKS) and electron spectrometer (Enge) implemented in new configuration, the so called 'Tilt Method'. Production data was taken on multiple targets: CH{sub 2}, {sup 6}Li, {sup 7}Li, {sup 9}Be, {sup 10}B, {sup 12}C and {sup 28}Si. In present study the analysis of CH{sub 2}, {sup 12}C and {sup 28}Si is presented. The elementary processes of p(e,e{prime}K{sup +}){Lambda}/{Sigma} from CH{sup 2} data were used for calibration of the spectrometer optics and kinematics. The hypernuclear spectra of {sup 12}{sub {Lambda}}B was obtained with ground state resolution of 0.47 {+-} 0.07 MeV (FWHM), the best ever achieved. Feasibility of the electroproduction reaction to study medium to heavy targets has been proven with the first high resolution beyond p-shell hypernuclear spectra from {sup 28}{sub {Lambda}}Al hypernuclei. The obtained results of the E01-011 experiment confirmed that hypernuclear spectroscopy by the (e,e{prime}K{sup +}) reaction is a very useful technique.

  20. Characterization of the Electronic and Chemical Structure at the Thin Film Solar Cell Interfaces: June 2005 -- June 2009

    SciTech Connect (OSTI)

    Heske, C.

    2009-09-01

    Study using photoelectron spectroscopy, inverse photoemission, and X-ray absorption and emission to derive the electronic structure of interfaces in CIGSS and CdTe thin-film solar cells.

  1. Experimental Station 8-2 | Stanford Synchrotron Radiation Lightsource

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    for controlling a temperature (4 - 350 K) and pressure (10-4 10-11 Torr) during XAS measurement. Status Open Supported Techniques Photoemission spectroscopy Soft x-ray...

  2. Crystallographic, electronic, thermal, and magnetic properties of single-crystal SrCo2As2

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Pandey, Abhishek; Quirinale, D. G.; Jayasekara, W.; Sapkota, A.; Kim, M. G.; Dhaka, R. S.; Lee, Y.; Heitmann, T. W.; Stephens, P. W.; Ogloblichev, V.; et al

    2013-07-01

    In tetragonal SrCo2As2 single crystals, inelastic neutron scattering measurements demonstrated that strong stripe-type antiferromagnetic (AFM) correlations occur at a temperature T = 5 K [W. Jayasekara et al., arXiv:1306.5174] that are the same as in the isostructural AFe2As2 (A = Ca, Sr, Ba) parent compounds of high-Tc superconductors. This surprising discovery suggests that SrCo2As2 may also be a good parent compound for high-Tc superconductivity. Here, structural and thermal expansion, electrical resistivity ρ, angle-resolved photoemission spectroscopy (ARPES), heat capacity Cp, magnetic susceptibility χ, 75As NMR and neutron diffraction measurements of SrCo2As2 crystals are reported together with LDA band structure calculations thatmore » shed further light on this fascinating material. The c-axis thermal expansion coefficient αc is negative from 7 to 300 K, whereas αa is positive over this T range. The ρ(T) shows metallic character. The ARPES measurements and band theory confirm the metallic character and in addition show the presence of a flat band near the Fermi energy EF. The band calculations exhibit an extremely sharp peak in the density of states D(EF) arising from a flat dx2-y2 band. A comparison of the Sommerfeld coefficient of the electronic specific heat with χ(T → 0) suggests the presence of strong ferromagnetic itinerant spin correlations which on the basis of the Stoner criterion predicts that SrCo2As2 should be an itinerant ferromagnet, in conflict with the magnetization data. The χ(T) does have a large magnitude, but also exhibits a broad maximum at 115 K suggestive of dynamic short-range AFM spin correlations, in agreement with the neutron scattering data. The measurements show no evidence for any type of phase transition between 1.3 and 300 K and we propose that metallic SrCo2As2 has a gapless quantum spin-liquid ground state.« less

  3. Crystallographic, electronic, thermal, and magnetic properties of single-crystal SrCo2As2

    SciTech Connect (OSTI)

    Pandey, Abhishek; Quirinale, D. G.; Jayasekara, W.; Sapkota, A.; Kim, M. G.; Dhaka, R. S.; Lee, Y.; Heitmann, T. W.; Stephens, P. W.; Ogloblichev, V.; Kreyssig, A.; McQueeney, R. J.; Goldman, A. I.; Kaminski, Adam; Harmon, B. N.; Furukawa, Y.; Johnston, D. C.

    2013-07-01

    In tetragonal SrCo2As2 single crystals, inelastic neutron scattering measurements demonstrated that strong stripe-type antiferromagnetic (AFM) correlations occur at a temperature T = 5 K [W. Jayasekara et al., arXiv:1306.5174] that are the same as in the isostructural AFe2As2 (A = Ca, Sr, Ba) parent compounds of high-Tc superconductors. This surprising discovery suggests that SrCo2As2 may also be a good parent compound for high-Tc superconductivity. Here, structural and thermal expansion, electrical resistivity ?, angle-resolved photoemission spectroscopy (ARPES), heat capacity Cp, magnetic susceptibility ?, 75As NMR and neutron diffraction measurements of SrCo2As2 crystals are reported together with LDA band structure calculations that shed further light on this fascinating material. The c-axis thermal expansion coefficient ?c is negative from 7 to 300 K, whereas ?a is positive over this T range. The ?(T) shows metallic character. The ARPES measurements and band theory confirm the metallic character and in addition show the presence of a flat band near the Fermi energy EF. The band calculations exhibit an extremely sharp peak in the density of states D(EF) arising from a flat dx2-y2 band. A comparison of the Sommerfeld coefficient of the electronic specific heat with ?(T ? 0) suggests the presence of strong ferromagnetic itinerant spin correlations which on the basis of the Stoner criterion predicts that SrCo2As2 should be an itinerant ferromagnet, in conflict with the magnetization data. The ?(T) does have a large magnitude, but also exhibits a broad maximum at 115 K suggestive of dynamic short-range AFM spin correlations, in agreement with the neutron scattering data. The measurements show no evidence for any type of phase transition between 1.3 and 300 K and we propose that metallic SrCo2As2 has a gapless quantum spin-liquid ground state.

  4. Evidence against a charge density wave on Bi(111)

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Kim, T. K.; Wells, J.; Kirkegaard, C.; Li, Z.; Hoffmann, S. V.; Gayone, J. E.; Fernandez-Torrente, I.; Häberle, P.; Pascual, J. I.; Moore, K. T.; et al

    2005-08-18

    The Bi(111) surface was studied by scanning tunneling microscopy (STM), transmission electron microscopy (TEM) and angle-resolved photoemission (ARPES) in order to verify the existence of a recently proposed surface charge density wave (CDW). The STM and TEM results to not support a CDW scenario at low temperatures. Thus the quasiparticle interference pattern observed in STM confirms the spin-orbit split character of the surface states which prevents the formation of a CDW, even in the case of good nesting. The dispersion of the electronic states observed with ARPES agrees well with earlier findings. In particular, the Fermi contour of the electronmore » pocket at the centre of the surface Brillouin zone is found to have a hexagonal shape. However, no gap opening or other signatures of a CDW phase transition can be found in the temperature-dependent data.« less

  5. Effects of charge inhomogeneities on elementary excitations in La2-xSrxCuO₄

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Park, S. R.; Hamann, A.; Pintschovius, L.; Lamago, D.; Khaliullin, G.; Fujita, M.; Yamada, K.; Gu, G. D.; Tranquada, J. M.; Reznik, D.

    2011-12-12

    Purely local experimental probes of many copper oxide superconductors show that their electronic states are inhomogeneous in real space. For example, scanning tunneling spectroscopic imaging shows strong variations in real space, and according to nuclear quadrupole resonance (NQR) studies, the charge distribution in the bulk varies on the nanoscale. However, the analysis of the experimental results utilizing spatially averaged probes often ignores this fact. We have performed a detailed investigation of the doping dependence of the energy and linewidth of the zone-boundary Cu-O bond-stretching vibration in La2-xSrxCuO₄ by inelastic neutron scattering. Both our results as well as previously reported angle-dependentmore » momentum widths of the electronic spectral function detected by angle-resolved photoemission can be reproduced by including the same distribution of local environments extracted from the NQR analysis.« less

  6. Quasiparticle interference, quasiparticle interactions, and the origin of the charge density wave in 2H-NbSe?

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Arguello, C. J.; Valla, T.; Rosenthal, E. P.; Andrade, E. F.; Jin, W.; Yeh, P. C.; Zaki, N.; Jia, S.; Cava, R. J.; Fernandes, R. M.; et al

    2015-01-20

    We show that a small number of intentionally introduced defects can be used as a spectroscopic tool to amplify quasiparticle interference in 2H-NbSe?, that we measure by scanning tunneling spectroscopic imaging. We show from the momentum and energy dependence of the quasiparticle interference that Fermi surface nesting is inconsequential to charge density wave formation in 2H-NbSe?. We demonstrate that by combining quasiparticle interference data with additional knowledge of the quasiparticle band structure from angle resolved photoemission measurements, one can extract the wavevector and energy dependence of the important electronic scattering processes thereby obtaining direct information both about the fermiology andmorethe interactions. In 2H-NbSe?, we use this combination to show that the important near-Fermi-surface electronic physics is dominated by the coupling of the quasiparticles to soft mode phonons at a wave vector different from the CDW ordering wave vector.less

  7. Quasiparticle interference, quasiparticle interactions, and the origin of the charge density wave in 2H–NbSe2

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Arguello, C. J.; Rosenthal, E. P.; Andrade, E. F.; Jin, W.; Yeh, P. C.; Zaki, N.; Jia, S.; Cava, R. J.; Fernandes, R. M.; Millis, A. J.; et al

    2015-01-21

    We show that a small number of intentionally introduced defects can be used as a spectroscopic tool to amplify quasiparticle interference in 2H-NbSe₂, that we measure by scanning tunneling spectroscopic imaging. We show from the momentum and energy dependence of the quasiparticle interference that Fermi surface nesting is inconsequential to charge density wave formation in 2H-NbSe₂. Thus, we demonstrate that by combining quasiparticle interference data with additional knowledge of the quasiparticle band structure from angle resolved photoemission measurements, one can extract the wavevector and energy dependence of the important electronic scattering processes thereby obtaining direct information both about the fermiologymore » and the interactions. In 2H-NbSe₂, we use this combination to show that the important near-Fermi-surface electronic physics is dominated by the coupling of the quasiparticles to soft mode phonons at a wave vector different from the CDW ordering wave vector.« less

  8. Measuring depth profiles of residual stress with Raman spectroscopy

    SciTech Connect (OSTI)

    Enloe, W.S.; Sparks, R.G.; Paesler, M.A.

    1988-12-01

    Knowledge of the variation of residual stress is a very important factor in understanding the properties of machined surfaces. The nature of the residual stress can determine a part`s susceptibility to wear deformation, and cracking. Raman spectroscopy is known to be a very useful technique for measuring residual stress in many materials. These measurements are routinely made with a lateral resolution of 1{mu}m and an accuracy of 0.1 kbar. The variation of stress with depth; however, has not received much attention in the past. A novel technique has been developed that allows quantitative measurement of the variation of the residual stress with depth with an accuracy of 10nm in the z direction. Qualitative techniques for determining whether the stress is varying with depth are presented. It is also demonstrated that when the stress is changing over the volume sampled, errors can be introduced if the variation of the stress with depth is ignored. Computer aided data analysis is used to determine the depth dependence of the residual stress.

  9. Laser-induced breakdown spectroscopy in industrial and security applications

    SciTech Connect (OSTI)

    Bol'shakov, Alexander A.; Yoo, Jong H.; Liu Chunyi; Plumer, John R.; Russo, Richard E.

    2010-05-01

    Laser-induced breakdown spectroscopy (LIBS) offers rapid, localized chemical analysis of solid or liquid materials with high spatial resolution in lateral and depth profiling, without the need for sample preparation. Principal component analysis and partial least squares algorithms were applied to identify a variety of complex organic and inorganic samples. This work illustrates how LIBS analyzers can answer a multitude of real-world needs for rapid analysis, such as determination of lead in paint and children's toys, analysis of electronic and solder materials, quality control of fiberglass panels, discrimination of coffee beans from different vendors, and identification of generic versus brand-name drugs. Lateral and depth profiling was performed on children's toys and paint layers. Traditional one-element calibration or multivariate chemometric procedures were applied for elemental quantification, from single laser shot determination of metal traces at {approx}10 {mu}g/g to determination of halogens at 90 {mu}g/g using 50-shot spectral accumulation. The effectiveness of LIBS for security applications was demonstrated in the field by testing the 50-m standoff LIBS rasterizing detector.

  10. Local spectroscopy of a kondo impurity: Co on Au(111)

    SciTech Connect (OSTI)

    Madhavan, V.; Chen, W.; Jamneala, T.; Crommie, M.F.; Wingreen, N.S.

    2001-07-15

    We present a detailed study of the local electronic properties of the Kondo system formed from cobalt adatoms deposited onto Au(111) at a temperature of 6.6 K. Cryogenic scanning-tunneling spectroscopy was used to observe impurity-induced resonances at the Fermi energy and at the Au(111) surface-state band edge. The line shape of the Fermi-energy resonance, identified as a Kondo resonance, is observed to vary with lateral position from the impurity center and with impurity binding position on the reconstructed Au(111) surface. Little vertical dependence is seen in the resonance line shape for positions above the center of the impurity. Interaction effects between Kondo impurities are observed to remain small as cobalt coverage is increased up to 1 ML on the gold surface. The Kondo resonance is shown theoretically to be a member of a general class of Fano resonances arising from the interaction of a discrete impurity state with a conduction-electron continuum. The asymmetric line shape of the resonance thus reflects quantum interference between the d orbital and continuum conduction electron channels, as well as their coupling to the STM tip.

  11. Method of using a nuclear magnetic resonance spectroscopy standard

    DOE Patents [OSTI]

    Spicer, Leonard D.; Bennett, Dennis W.; Davis, Jon F.

    1985-01-01

    (CH.sub.3).sub.3 SiNSO is produced by the reaction of ((CH.sub.3).sub.3 Si).sub.2 NH with SO.sub.2. Also produced in the reaction are ((CH.sub.3).sub.3 Si).sub.2 O and a new solid compound [NH.sub.4 ][(CH.sub.3).sub.3 SiOSO.sub.2 ]. Both (CH.sub.3).sub.3 SiNSO and [NH.sub.4 ][(CH.sub.3).sub.3 SiOSO.sub.2 ] have fluorescent properties. The reaction of the subject invention is used in a method of measuring the concentration of SO.sub.2 pollutants in gases. By the method, a sample of gas is bubbled through a solution of ((CH.sub.3).sub.3 Si).sub.2 NH, whereby any SO.sub.2 present in the gas will react to produce the two fluorescent products. The measured fluorescence of these products can then be used to calculate the concentration of SO.sub.2 in the original gas sample. The solid product [NH.sub.4 ][(CH.sub.3).sub.3 SiOSO.sub.2 ] may be used as a standard in solid state NMR spectroscopy, wherein the resonance peaks of either .sup.1 H, .sup.13 C, .sup.15 N, or .sup.29 Si may be used as a reference.

  12. Computational expressions for signals in frequency-modulation spectroscopy

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Di Rosa, Michael D.; Reiten, M. T.

    2015-05-25

    In this study, general expressions for the signals in frequency-modulation spectroscopy (FMS) appear in the literature but are often reduced to simple analytical equations following the assumption of a weak modulation index. This is little help to the experimentalist who wants to predict signals for modulation depths of the order of unity or greater, where strong FMS signals reside. Here, we develop general formulas for FMS signals in the case of an absorber with a Voigt line shape and then link these expressions to an example and existing numerical code for the line shape. The resulting computational recipe is easymore » to implement and exercised here to show where the larger FMS signals are found over the coordinates of modulation index and modulation frequency. One can also estimate from provided curves the in-phase FMS signal over a wide range of modulation parameters at either the Lorentzian-broadening or Doppler-broadening limit, or anywhere in between by interpolation.« less

  13. Photoelectron spectroscopy of wet and gaseous samples through graphene membranes

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Kraus, Jrgen; Reichelt, Robert; Gnther, Sebastian; Gregoratti, Luca; Amati, Matteo; Kiskinova, Maya; Yulaev, Alexander; Vlassiouk, Ivan V.; Kolmakov, Andrei

    2014-09-21

    Photoelectron spectroscopy (PES) and microscopy are highly important for exploring morphologically and chemically complex liquidgas, solidliquid and solidgas interfaces under realistic conditions, but the very small electron mean free path inside dense media imposes serious experimental challenges. Currently, near ambient pressure PES is conducted using dexterously designed electron energy analyzers coupled with differentially pumped electron lenses which make it possible to conduct PES measurements at a few hPa. This report proposes an alternative ambient pressure approach that can be applied to a broad class of samples and be implemented in conventional PES instruments. It uses ultrathin electron transparent but molecularmoreimpermeable membranes to isolate the high pressure sample environment from the high vacuum PES detection system. We show that the separating graphene membrane windows are both mechanically robust and sufficiently transparent for electrons in a wide energy range to allow soft X-ray PES of liquid and gaseous water. The performed proof-of-principle experiments confirm the possibility to probe vacuum-incompatible toxic or reactive samples placed inside such hermetic, gas flow or fluidic environmental cells.less

  14. Multiplicative or t1 Noise in NMR Spectroscopy

    SciTech Connect (OSTI)

    Granwehr, Josef

    2005-01-25

    The signal in an NMR experiment is highly sensitive to fluctuations of the environment of the sample. If, for example, the static magnetic field B{sub 0}, the amplitude and phase of radio frequency (rf) pulses, or the resonant frequency of the detection circuit are not perfectly stable and reproducible, the magnetic moment of the spins is altered and becomes a noisy quantity itself. This kind of noise not only depends on the presence of a signal, it is in fact proportional to it. Since all the spins at a particular location in a sample experience the same environment at any given time, this noise primarily affects the reproducibility of an experiment, which is mainly of importance in the indirect dimensions of a multidimensional experiment, when intense lines are suppressed with a phase cycle, or for difference spectroscopy techniques. Equivalently, experiments which are known to be problematic with regard to their reproducibility, like flow experiments or experiments with a mobile target, tend to be affected stronger by multiplicative noise. In this article it is demonstrated how multiplicative noise can be identified and characterized using very simple, repetitive experiments. An error estimation approach is developed to give an intuitive, yet quantitative understanding of its properties. The consequences for multidimensional NMR experiments are outlined, implications for data analysis are shown, and strategies for the optimization of experiments are summarized.

  15. Two-dimensional electronic spectroscopy signatures of the glass transition

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Lewis, K. L. .M.; Myers, J. A.; Fuller, F.; Tekavec, P. F.; Ogilvie, J. P.

    2010-01-01

    Two-dimensional electronic spectroscopy is a sensitive probe of solvation dynamics. Using a pump–probe geometry with a pulse shaper [ Optics Express 15 (2007), 16681-16689; Optics Express 16 (2008), 17420-17428], we present temperature dependent 2D spectra of laser dyes dissolved in glass-forming solvents. At low waiting times, the system has not yet relaxed, resulting in a spectrum that is elongated along the diagonal. At longer times, the system loses its memory of the initial excitation frequency, and the 2D spectrum rounds out. As the temperature is lowered, the time scale of this relaxation grows, and the elongation persists for longermore » waiting times. This can be measured in the ratio of the diagonal width to the anti-diagonal width; the behavior of this ratio is representative of the frequency–frequency correlation function [ Optics Letters 31 (2006), 3354–3356]. Near the glass transition temperature, the relaxation behavior changes. Understanding this change is important for interpreting temperature-dependent dynamics of biological systems.« less

  16. Fluorescence Correlation Spectroscopy at Micromolar Concentrations without Optical Nanoconfinement

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Laurence, Ted A.; Ly, Sonny; Bourguet, Feliza; Fischer, Nicholas O.; Coleman, Matthew A.

    2014-08-14

    Fluorescence correlation spectroscopy (FCS) is an important technique for studying biochemical interactions dynamically that may be used in vitro and in cell-based studies. It is generally claimed that FCS may only be used at nM concentrations. We show that this general consensus is incorrect and that the limitation to nM concentrations is not fundamental but due to detector limits as well as laser fluctuations. With a high count rate detector system and applying laser fluctuation corrections, we demonstrate FCS measurements up to 38 μM with the same signal-to-noise as at lower concentrations. Optical nanoconfinement approaches previously used to increase themore » concentration range of FCS are not necessary, and further increases above 38 μM may be expected using detectors and detector arrays with higher saturation rates and better laser fluctuation corrections. This approach greatly widens the possibilities of dynamic measurements of biochemical interactions using FCS at physiological concentrations.« less

  17. Bismuth-Loaded Polymer Scintillators for Gamma Ray Spectroscopy

    SciTech Connect (OSTI)

    Rupert, B L; Cherepy, N J; Sturm, B W; Sanner, R D; Dai, Z; Payne, S A

    2011-04-11

    We synthesize a series of polyvinylcarbazole monoliths containing varying loadings of triphenyl bismuth as a high-Z dopant and varying fluors, either organic or organometallic, in order to study their use as scintillators capable of gamma ray spectroscopy. A trend of increasing bismuth loading resulting in a better-resolved photopeak is observed. For PVK parts with no fluor or a standard organic fluor, diphenylanthracene, increasing bismuth loading results in decreasing light yield while with samples 1 or 3 % by weight of the spin-orbit coupling organometallic fluor FIrpic, which emits light from both singlet and triple excitons, show increasing light yield with increasing bismuth loading. Our best performing PVK/ BiPh{sub 3}/FIrpic scintillator with 40 wt % BiPh3 and 3 wt % FIrpic has an emission maximum of 500 nm, a light yield of {approx}30,000 photons/MeV, and energy resolution better than 7% FWHM at 662 keV. Replacing the Ir complex with an equal weight of diphenylanthracene produces a sample with a light yield of {approx}6,000 photons/MeV, with an emission maximum at 420 nm and energy resolution of 9% at 662 keV. Transmission electron microscopy studies show that the BiPh{sub 3} forms small clusters of approximately 5 nm diameter.

  18. Optical heterodyne detection for cavity ring-down spectroscopy

    DOE Patents [OSTI]

    Levenson, Marc D. (Saratoga, CA); Paldus, Barbara A. (Mountain View, CA); Zare, Richard N. (Stanford, CA)

    2000-07-25

    A cavity ring-down system for performing cavity ring-down spectroscopy (CRDS) using optical heterodyne detection of a ring-down wave E.sub.RD during a ring-down phase or a ring-up wave E.sub.RU during a ring up phase. The system sends a local oscillator wave E.sub.LO and a signal wave E.sub.SIGNAL to the cavity, preferably a ring resonator, and derives an interference signal from the combined local oscillator wave E.sub.LO and the ring-down wave E.sub.RD (or ring-up wave E.sub.RU). The local oscillator wave E.sub.LO has a first polarization and the ring-down wave E.sub.RD has a second polarization different from the first polarization. The system has a combining arrangement for combining or overlapping local oscillator wave E.sub.LO and the ring-down wave E.sub.RD at a photodetector, which receives the interference signal and generates a heterodyne current I.sub.H therefrom. Frequency and phase differences between the waves are adjustable.

  19. An Analog Filter Approach to Frequency Domain Fluorescence Spectroscopy

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Trainham, Clifford P.; O'Neill, Mary D.; McKenna, Ian J.

    2015-04-24

    The rate equations found in frequency domain fluorescence spectroscopy are the same as those found in electronics under analog filter theory. Laplace transform methods are a natural way to solve the equations, and the methods can provide solutions for arbitrary excitation functions. The fluorescence terms can be modeled as circuit components and cascaded with drive and detection electronics to produce a global transfer function. Electronics design tools such as Spicea can be used to model fluorescence problems. In applications, such as remote sensing, where detection electronics are operated at high gain and limited bandwidth, a global modeling of the entiremore » system is important, since the filter terms of the drive and detection electronics affect the measured response of the fluorescence signals. The techniques described here can be used to separate signals from fast and slow fluorophores emitting into the same spectral band, and data collection can be greatly accelerated by means of a frequency comb driver waveform and appropriate signal processing of the response.« less

  20. Strontium Iodide Instrument Development for Gamma Spectroscopy and Radioisotope Identification

    SciTech Connect (OSTI)

    Beck, P; Cherepy, Nerine; Payne, Stephen A.; Swanberg, E.; Nelson, K.; Thelin, P; Fisher, S E; Hunter, Steve; Wihl, B; Shah, Kanai; Hawrami, Rastgo; Burger, Arnold; Boatner, Lynn A; Momayezi, M; Stevens, K; Randles, M H; Solodovnikov, D

    2014-01-01

    Development of the Europium-doped Strontium Iodide scintillator, SrI2(Eu), has progressed significantly in recent years. SrI2(Eu) has excellent material properties for gamma ray spectroscopy: high light yield (>80,000 ph/MeV), excellent light yield proportionality, and high effective atomic number (Z=49) for high photoelectric cross-section. High quality 1.5 and 2 diameter boules are now available due to rapid advances in SrI2(Eu) crystal growth. In these large SrI2(Eu) crystals, optical self-absorption by Eu2+ degrades the energy resolution as measured by analog electronics, but we mitigate this effect through on-the-fly correction of the scintillation pulses by digital readout electronics. Using this digital correction technique we have demonstrated energy resolution of 2.9% FWHM at 662 keV for a 4 in3 SrI2(Eu) crystal, over 2.6 inches long. Based on this digital readout technology, we have developed a detector prototype with greatly improved radioisotope identification capability compared to Sodium Iodide, NaI(Tl). The higher resolution of SrI2(Eu) yields a factor of 2 to 5 improvement in radioisotope identification (RIID) error rate compared to NaI(Tl).

  1. OSIRIS - Gamma-Ray Spectroscopy Software for On-Site Inspections under the Comprehensive Nuclear-Test-Ban Treaty

    SciTech Connect (OSTI)

    Caffrey, Augustine J.; Bowyer, Ted W.; Egger, A. E.; Hall, Jeter C.; Kelly, S. M.; Krebs, K. M.; Kreek, S.; Jordan, David V.; Milbrath, Brian D.; Padgett, Stephen W.; Wharton, C. J.; Wimer, Nathan G.

    2015-06-01

    OSIRIS - Gamma-Ray Spectroscopy Software for On-Site Inspections under the Comprehensive Nuclear-Test-Ban Treaty

  2. In-flight hadron spectroscopy at LEAR (Journal Article) | SciTech Connect

    Office of Scientific and Technical Information (OSTI)

    In-flight hadron spectroscopy at LEAR Citation Details In-Document Search Title: In-flight hadron spectroscopy at LEAR In this paper, I present the most recent hadron spectroscopy results stemming from in-flight p-barp reactions at LEAR. In the mass range from approximately 2.0 to 2.43 GeV, scans for both broad and narrow resonances have been performed. The PS185, Crystal Barrel and Jetset experiments figure prominently in the results presented. Particular attention is given to the latest

  3. Laser-induced breakdown spectroscopy of alkali metals in high-temperature

    Office of Scientific and Technical Information (OSTI)

    gas (Journal Article) | SciTech Connect Laser-induced breakdown spectroscopy of alkali metals in high-temperature gas Citation Details In-Document Search Title: Laser-induced breakdown spectroscopy of alkali metals in high-temperature gas Laser-induced breakdown spectroscopy (LIBS) measurements of alkali in the high-temperature exhaust of a glass furnace show an attenuation of the Na and K LIBS signals that correlates with the stoichiometry of the bath gas surrounding the spark. The results

  4. A first site of galaxy cluster formation: complete spectroscopy of a

    Office of Scientific and Technical Information (OSTI)

    protocluster at z = 6.01 (Journal Article) | SciTech Connect A first site of galaxy cluster formation: complete spectroscopy of a protocluster at z = 6.01 Citation Details In-Document Search Title: A first site of galaxy cluster formation: complete spectroscopy of a protocluster at z = 6.01 We performed a systematic spectroscopic observation of a protocluster at z = 6.01 in the Subaru Deep Field. We took spectroscopy for all 53 i' dropout galaxies down to z' = 27.09 mag in/around the

  5. Enhanced visible and near-infrared capabilities of the JET mirror-linked divertor spectroscopy system

    SciTech Connect (OSTI)

    Lomanowski, B. A. Sharples, R. M.; Meigs, A. G.; Conway, N. J.; Zastrow, K.-D.; Heesterman, P.; Kinna, D. [EURATOM Collaboration: JET-EFDA Team

    2014-11-15

    The mirror-linked divertor spectroscopy diagnostic on JET has been upgraded with a new visible and near-infrared grating and filtered spectroscopy system. New capabilities include extended near-infrared coverage up to 1875 nm, capturing the hydrogen Paschen series, as well as a 2 kHz frame rate filtered imaging camera system for fast measurements of impurity (Be II) and deuterium D?, D?, D? line emission in the outer divertor. The expanded system provides unique capabilities for studying spatially resolved divertor plasma dynamics at near-ELM resolved timescales as well as a test bed for feasibility assessment of near-infrared spectroscopy.

  6. Nanocrystalline zinc ferrite films studied by magneto-optical spectroscopy

    SciTech Connect (OSTI)

    Likov-Jakubisov, E. Vi?ovsk, .; irok, P.; Hrabovsk, D.; Pitora, J.; Sahoo, Subasa C.; Prasad, Shiva; Venkataramani, N.; Bohra, Murtaza; Krishnan, R.

    2015-05-07

    Ferrimagnetic Zn-ferrite (ZnFe{sub 2}O{sub 4}) films can be grown with the ferromagnetic resonance linewidth of 40?Oe at 9.5?GHz without going through a high temperature processing. This presents interest for applications. The work deals with laser ablated ZnFe{sub 2}O{sub 4} films deposited at O{sub 2} pressure of 0.16?mbar onto fused quartz substrates. The films about 120?nm thick are nanocrystalline and their spontaneous magnetization, 4?M{sub s}, depends on the nanograin size, which is controlled by the substrate temperature (T{sub s}). At T{sub s}???350?C, where the grain distribution peaks around ?2030?nm, the room temperature 4?M{sub s} reaches a maximum of ?2.3?kG. The films were studied by magnetooptical polar Kerr effect (MOKE) spectroscopy at photon energies between 1 and 5?eV. The complementary characteristics were provided by spectral ellipsometry (SE). Both the SE and MOKE spectra confirmed ferrimagnetic ordering. The structural details correspond to those observed in MgFe{sub 2}O{sub 4} and Li{sub 0.5}Fe{sub 2.5}O{sub 4} spinels. SE experiments confirm the insulator behavior. The films display MOKE amplitudes somewhat reduced with respect to those in Li{sub 0.5}Fe{sub 2.5}O{sub 4} and MgFe{sub 2}O{sub 4} due to a lower degree of spinel inversion and nanocrystalline structure. The results indicate that the films are free of oxygen vacancies and Fe{sup 3+}-Fe{sup 2+} exchange.

  7. Non-linear optical studies of adsorbates: Spectroscopy and dynamics

    SciTech Connect (OSTI)

    Zhu, Xiangdong.

    1989-08-01

    In the first part of this thesis, we have established a systematic procedure to apply the surface optical second-harmonic generation (SHG) technique to study surface dynamics of adsorbates. In particular, we have developed a novel technique for studies of molecular surface diffusions. In this technique, the laser-induced desorption with two interfering laser beams is used to produce a monolayer grating of adsorbates. The monolayer grating is detected with diffractions of optical SHG. By monitoring the first-order second-harmonic diffraction, we can follow the time evolution of the grating modulation from which we are able to deduce the diffusion constant of the adsorbates on the surface. We have successfully applied this technique to investigate the surface diffusion of CO on Ni(111). The unique advantages of this novel technique will enable us to readily study anisotropy of a surface diffusion with variable grating orientation, and to investigate diffusion processes of a large dynamic range with variable grating spacings. In the second part of this work, we demonstrate that optical infrared-visible sum-frequency generation (SFG) from surfaces can be used as a viable surface vibrational spectroscopic technique. We have successfully recorded the first vibrational spectrum of a monolayer of adsorbates using optical infrared-visible SFG. The qualitative and quantitative correlation of optical SFG with infrared absorption and Raman scattering spectroscopies are examined and experimentally demonstrated. We have further investigated the possibility to use transient infrared-visible SFG to probe vibrational transients and ultrafast relaxations on surfaces. 146 refs.

  8. Johann Spectrometer for High Resolution X-ray Spectroscopy

    SciTech Connect (OSTI)

    Machek, Pavel; Froeba, Michael; Welter, Edmund; Caliebe, Wolfgang; Brueggmann, Ulf; Draeger, Guenter

    2007-01-19

    A newly designed vacuum Johann spectrometer with a large focusing analyzer crystal for inelastic x-ray scattering and high resolution fluorescence spectroscopy has been installed at the DORIS III storage ring. Spherically bent crystals with a maximum diameter of 125 mm, and cylindrically bent crystals are employed as dispersive optical elements. Standard radius of curvature of the crystals is 1000 mm, however, the design of the mechanical components also facilitates measurements with smaller and larger bending radii. Up to four crystals are mounted on a revolving crystal changer which enables crystal changes without breaking the vacuum. The spectrometer works at fixed Bragg angle. It is preferably designed for the measurements in non-scanning mode with a broad beam spot, and offers a large flexibility to set the sample to the optimum position inside the Rowland circle. A deep depletion CCD camera is employed as a position sensitive detector to collect the energy-analyzed photons on the circumference of the Rowland circle. The vacuum in the spectrometer tank is typically 10-6 mbar. The sample chamber is separated from the tank either by 25 {mu}m thick Kapton windows, which allows samples to be measured under ambient conditions, or by two gate valves. The spectrometer is currently installed at wiggler beamline W1 whose working range is 4-10.5 keV with typical flux at the sample of 5x1010photons/s/mm2. The capabilities of the spectrometer are illustrated by resonant inelastic experiments on 3d transition metals and rare earth compounds, and by chemical shift measurements on chromium compounds.

  9. Monitoring PVD metal vapors using laser absorption spectroscopy

    SciTech Connect (OSTI)

    Braun, D.G.; Anklam, T.M.; Berzins, L.V.; Hagans, K.G.

    1994-04-01

    Laser absorption spectroscopy (LAS) has been used by the Atomic Vapor Laser Isotope Separation (AVLIS) program for over 10 years to monitor the co-vaporization of uranium and iron in its separators. During that time, LAS has proven to be an accurate and reliable method to monitor both the density and composition of the vapor. It has distinct advantages over other rate monitors, in that it is completely non-obtrusive to the vaporization process and its accuracy is unaffected by the duration of the run. Additionally, the LAS diagnostic has been incorporated into a very successful process control system. LAS requires only a line of sight through the vacuum chamber, as all hardware is external to the vessel. The laser is swept in frequency through an absorption line of interest. In the process a baseline is established, and the line integrated density is determined from the absorption profile. The measurement requires no hardware calibration. Through a proper choice of the atomic transition, a wide range of elements and densities have been monitored (e.g. nickel, iron, cerium and gadolinium). A great deal of information about the vapor plume can be obtained from the measured absorption profiles. By monitoring different species at the same location, the composition of the vapor is measured in real time. By measuring the same density at different locations, the spatial profile of the vapor plume is determined. The shape of the absorption profile is used to obtain the flow speed of the vapor. Finally, all of the above information is used evaluate the total vaporization rate.

  10. Femtosecond stimulated Raman spectroscopy by six-wave mixing

    SciTech Connect (OSTI)

    Molesky, Brian P.; Guo, Zhenkun; Moran, Andrew M.

    2015-06-07

    Femtosecond Stimulated Raman Spectroscopy (FSRS) is motivated by the knowledge of the molecular geometry changes that accompany sub-picosecond chemical reactions. The detection of vibrational resonances throughout the entire fingerprint region of the spectrum with sub-100-fs delay precision is fairly straightforward to accomplish with the FSRS technique. Despite its utility, FSRS must contend with substantial technical challenges that stem from a large background of residual laser light and lower-order nonlinearities when all laser pulses are electronically resonant with the equilibrium system. In this work, a geometry based on five incident laser beams is used to eliminate much of this undesired background in experiments conducted on metmyoglobin. Compared to a three-beam FSRS geometry with all electronically resonant laser pulses, the five-beam approach described here offers major improvements in the data acquisition rate, sensitivity, and background suppression. The susceptibility of the five-beam geometry to experimental artifacts is investigated using control experiments and model calculations. Of particular concern are undesired cascades of third-order nonlinearities, which are known to challenge FSRS measurements carried out on electronically off-resonant systems. It is generally understood that forbidden steps in the desired nonlinear optical processes are the origin of the problems encountered under off-resonant conditions. In contrast, the present experiments are carried out under electronically resonant conditions, where such unfortunate selection rules do not apply. Nonetheless, control experiments based on spectroscopic line shapes, signal phases, and sample concentrations are conducted to rule out significant contributions from cascades of third-order processes. Theoretical calculations are further used to estimate the relative intensities of the direct and cascaded responses. Overall, the control experiments and model calculations presented in this work suggest promise for multidimensional resonance Raman investigations of heme proteins.

  11. Hard x-ray delay line for x-ray photon correlation spectroscopy...

    Office of Scientific and Technical Information (OSTI)

    Hard x-ray delay line for x-ray photon correlation spectroscopy and jitter-free pump-probe experiments at LCLS Citation Details In-Document Search Title: Hard x-ray delay line for...

  12. Phonon spectroscopy with sub-meV resolution by femtosecond x...

    Office of Scientific and Technical Information (OSTI)

    Phonon spectroscopy with sub-meV resolution by femtosecond x-ray diffuse scattering Citation Details In-Document Search This content will become publicly available on August 9,...

  13. Two Novel x-ray Optical Schemes for Spectroscopy with Fast Time...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Two Novel x-ray Optical Schemes for Spectroscopy with Fast Time Resolution and Two-dimensional Imaging with High Magnification ---- Inventor(s) Manfred Bitter, Kenneth W. Hill,...

  14. Dual modulation laser line-locking technique for wavelength modulation spectroscopy

    DOE Patents [OSTI]

    Bomse, David S. (Santa Fe, NM); Hovde, D. Christian (Santa Fe, NM); Silver, Joel A. (Santa Fe, NM)

    2002-01-01

    Disclosed are a method and apparatus for dual modulation of an optical spectroscopy laser. Demodulation is accomplished in a manner resulting in measurement of absorbance of a gas species, as well as stabilization of laser wavelength and baseline noise reduction.

  15. In-situ X-ray Photoelectron Spectroscopy of a Catalyst for Artificial...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    In-situ X-ray Photoelectron Spectroscopy of a Catalyst for Artificial Photosynthesis Monday, June 30, 2014 Plants and other organisms use a process called photosynthesis to produce...

  16. A New Class of Focusing Crystal Surfaces for the Bragg Spectroscopy...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    New Class of Focusing Crystal Surfaces for the Bragg Spectroscopy of High-Density Plasmas and Small (point-like) X-Ray Sources This invention describes a general class of new...

  17. Novel CO2 Binding Mechanism Determined via in-situ Absorption Spectroscopy

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    & Theory | Center for Gas SeparationsRelevant to Clean Energy Technologies | Blandine Jerome Novel CO2 Binding Mechanism Determined via in-situ Absorption Spectroscopy & Theory

  18. Calibration of Spherically Bent Crystals used in X-Ray Spectroscopy...

    Office of Scientific and Technical Information (OSTI)

    Conference: Calibration of Spherically Bent Crystals used in X-Ray Spectroscopy. Citation Details In-Document Search Title: Calibration of Spherically Bent Crystals used in X-Ray...

  19. Femtosecond X-ray Absorption Spectroscopy at a Hard X-ray Free...

    Office of Scientific and Technical Information (OSTI)

    Femtosecond X-ray Absorption Spectroscopy at a Hard X-ray Free Electron Laser: Application to Spin Crossover Dynamics Citation Details In-Document Search Title: Femtosecond X-ray...

  20. X-Ray Spectroscopy of the Mn(4) Ca Cluster in the Water-Oxidation...

    Office of Scientific and Technical Information (OSTI)

    Ca Cluster in the Water-Oxidation Complex of Photosystem II Citation Details In-Document Search Title: X-Ray Spectroscopy of the Mn(4) Ca Cluster in the Water-Oxidation Complex ...

  1. Time-resolved Spectroscopy of Laser-heated Copper Foils | Stanford

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Synchrotron Radiation Lightsource Time-resolved Spectroscopy of Laser-heated Copper Foils Tuesday, July 16, 2013 - 11:00am SLAC, Conference Room 137-322 Presented by Kelly Cone, PhD Engineering, Dept. of Applied Science, University of California, Davis The volumetric heating of a thin copper target has been studied with time resolved x-ray spectroscopy. The copper target was heated by a plasma produced using the Lawrence Livermore National Laboratory's Compact Multipulse Terawatt (COMET)

  2. Quark Forces from Hadronic Spectroscopy (Journal Article) | SciTech Connect

    Office of Scientific and Technical Information (OSTI)

    Quark Forces from Hadronic Spectroscopy Citation Details In-Document Search Title: Quark Forces from Hadronic Spectroscopy We consider the implications of the most general two-body quark-quark interaction Hamiltonian for the spin-flavor structure of the negative parity L=1 excited baryons. Assuming the most general two-body quark interaction Hamiltonian, we derive two correlations among the masses and mixing angles of these states, which constrain the mixing angles, and can be used to test for

  3. Terahertz magneto-optical spectroscopy of a two-dimensional hole gas

    Office of Scientific and Technical Information (OSTI)

    (Journal Article) | SciTech Connect Terahertz magneto-optical spectroscopy of a two-dimensional hole gas Citation Details In-Document Search Title: Terahertz magneto-optical spectroscopy of a two-dimensional hole gas Two-dimensional hole gases (2DHGs) have attracted recent attention for their unique quantum physics and potential applications in areas including spintronics and quantum computing. However, their properties remain relatively unexplored, motivating the use of different techniques

  4. XAS and XMCD spectroscopies to study matter at high pressure: Probing the

    Office of Scientific and Technical Information (OSTI)

    correlation between structure and magnetism in the 3d metals (Journal Article) | SciTech Connect XAS and XMCD spectroscopies to study matter at high pressure: Probing the correlation between structure and magnetism in the 3d metals Citation Details In-Document Search Title: XAS and XMCD spectroscopies to study matter at high pressure: Probing the correlation between structure and magnetism in the 3d metals Authors: Torchio, R. ; Mathon, O. ; Pascarelli, S. [1] + Show Author Affiliations

  5. 31P-Edited Diffusion-Ordered 1H NMR Spectroscopy for the Isolation and

    Office of Scientific and Technical Information (OSTI)

    Identification of Organophosphorus Compounds Related to Chemical Weapons Agents and their Degradation Products (Journal Article) | SciTech Connect 31P-Edited Diffusion-Ordered 1H NMR Spectroscopy for the Isolation and Identification of Organophosphorus Compounds Related to Chemical Weapons Agents and their Degradation Products Citation Details In-Document Search Title: 31P-Edited Diffusion-Ordered 1H NMR Spectroscopy for the Isolation and Identification of Organophosphorus Compounds Related

  6. An internal report: Electron Spectroscopy of the Oxidation and Aging of U

    Office of Scientific and Technical Information (OSTI)

    and Pu (Technical Report) | SciTech Connect An internal report: Electron Spectroscopy of the Oxidation and Aging of U and Pu Citation Details In-Document Search Title: An internal report: Electron Spectroscopy of the Oxidation and Aging of U and Pu Uranium and Plutonium are highly reactive elements that undergo not only chemical reactions but also nuclear reactions. This can lead to possibly significant materials degradation, a matter of potentially great concern. Here, the issue of the

  7. Calibration of Spherically Bent Crystals used in X-Ray Spectroscopy.

    Office of Scientific and Technical Information (OSTI)

    (Conference) | SciTech Connect Conference: Calibration of Spherically Bent Crystals used in X-Ray Spectroscopy. Citation Details In-Document Search Title: Calibration of Spherically Bent Crystals used in X-Ray Spectroscopy. Authors: Patel, Sonal Publication Date: 2012-08-01 OSTI Identifier: 1060480 Report Number(s): SAND2012-6558C DOE Contract Number: AC04-94AL85000 Resource Type: Conference Resource Relation: Conference: Proposed for presentation at the SEERI Student Presentation held

  8. Ambient Pressure Photoelectron Spectroscopy Using Soft X-ray and Hard

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    X-ray, and its applications in electrochemistry | Stanford Synchrotron Radiation Lightsource Ambient Pressure Photoelectron Spectroscopy Using Soft X-ray and Hard X-ray, and its applications in electrochemistry Friday, December 14, 2012 - 3:30pm SSRL, Bldg. 137, room 322 Zhi Liu The synchrotron based ambient pressure x-ray photoelectron spectroscopy (AP-XPS) endstation[1] pioneered at ALS based on differentially pumped electron energy analyzer has been recognized by scientific communities as

  9. Propagating spectroscopy of backward volume spin waves in a metallic FeNi film

    SciTech Connect (OSTI)

    Sato, N.; Ishida, N.; Kawakami, T.; Sekiguchi, K.

    2014-01-20

    We report a propagating spin wave spectroscopy for a magnetostatic backward volume spin wave in a metallic Fe{sub 19}Ni{sub 81} film. We show that the mutual-inductance between two independent antennas detects a small but clear propagation signal of backward volume spin waves. All experimental data are consistent with the time-domain propagating spin-wave spectroscopy. The control of propagating backward spin wave enables to realize the miniaturize spin-wave circuit.

  10. SPECTROSCOPY OF ELECTROPRODUCED LIGHT TO MEDIUM MASS LAMBDA HYPERNUCLEI

    SciTech Connect (OSTI)

    Pavlo Baturin

    2010-07-13

    One of the main tasks of nuclear physics is the study of subatomic particles and their interactions. Nowadays, the fundamental theory of strong interactions is a particularly interesting subject in the field. At the current moment, such a theory is not complete yet. It describes very well the nucleon-nucleon (NN) interactions, which were intensively studied over the last several decades. In our modern, technically advanced world the research gravitates towards the higher energies, reaching deeper inside of the nuclear structure. About sixty years ago the strong interaction was associated with the interaction between nucleons responsible for holding those nucleons together within the nuclear volume. However, with discovery of mesons and strange particles, the picture has changed. The proof of bound states of strange baryons (? particles) with nucleons revealed a broad class of particles participating in the strong interaction, called hadrons. The rich variety of hadron interactions raises an important topic in modern nuclear physics which strives for providing a deep insight into nuclear matter structure. The analysis of the interaction of a strange baryon, called a hyperon, with a nucleon delivers new knowledge of nuclear properties, which were not understood with widely studied nucleon-nucleon interactions. The direct approach for creating an interaction of free hyperons with nucleons in the target is not an easy task in experimental nuclear physics. The relatively short lifetime of free hyperons, which can only be produced as a secondary beam, leads to extremely low statistics. Nowadays, the best known method of hyperon-nucleon interaction study is the formation of hyperons inside of the nucleus. The bound hyperon serves as a probe of nuclear properties of such complex nuclear systems called hypernuclei. Hypernuclear physics itself is a sub-area of nuclear physics, which studies such bound systems. It employs the rich knowledge of the nucleon-nucleon interaction and at the same time performs a generalization of the above mentioned interaction for systems with a third quark flavor strangeness [1]. Production reactions of ? particles and hypernuclei, as well as spectroscopy and decay modes, provide valuable information on the hyperon interaction. For example, analysis of ? and hypernuclear decay modes gives knowledge of the properties of weak interactions. The study of the energy of ground and excited states exposes the laws of baryon distribution inside of the nucleus. Investigation of ?N and ?? potentials is important for baryon-baryon theories that include strange quarks, e.g. SU(3). These potentials are more short-ranged than the ones for NN and therefore the additional degrees of freedom play an essential role.

  11. Electronic Band Structure And Kondo Coupling in YbRh(2)Si(2)

    SciTech Connect (OSTI)

    Wigger, G.A.; Baumberger, F.; Shen, Z.X.; Yin, Z.P.; Pickett, W.E.; Maquilon, S.; Fisk, Z.; /UC, Davis

    2007-09-26

    The electronic band structure of YbRh{sub 2}Si{sub 2} is calculated in a relativistic framework including correlation corrections and magnetization of the Yb ion and compared to detailed angle-resolved photoemission spectra. The photoemission spectra for LuRh{sub 2}Si{sub 2} are used as reference to identify electronic bands with no f symmetry. The calculated band structure manifests a 4f{sup 13} spin-polarized configuration leaving the unoccupied state at 1.4 eV above the Fermi energy. At the band theory level, the 4f bands are located far below the Fermi level and the anisotropic Coulomb interaction within the 4f shell spreads the multilevel into broader 4f complexes below -2.5 eV. The photoemission spectra obtained on YbRh2Si2 show a clear f-multilevel splitting into j=7/2 and 5/2 excitations. The interaction of the 4f{sub 7/2} levels close to the Fermi energy with two conduction bands shows visible hybridization gaps of 45 and 80 meV, respectively. We discuss the origin of these excitations and provide an analysis according to Anderson's single-impurity model with parameters suggested by the band-structure calculation and the photoemission spectra. Both experiment and theory indicate nearly identical Fermi surfaces for LuRh{sub 2}Si{sub 2} and YbRh{sub 2}Si{sub 2}. The valency of Yb in YbRh{sub 2}Si{sub 2} is estimated to be close to +3.

  12. 2012 VIBRATIONAL SPECTROSCOPY GORDON RESEARCH CONFERENCE, AUGUST 5-10, 2012

    SciTech Connect (OSTI)

    Geiger, Franz

    2012-08-10

    The Vibrational Spectroscopy conference brings together experimentalists and theoreticians working at the frontiers of modern vibrational spectroscopy, with a special emphasis on spectroscopies that probe the structure and dynamics of molecules in gases, liquids, and at interfaces. The conference explores the wide range of state-of-the-art techniques based on vibrational motion. These techniques span the fields of time-domain, high-resolution frequency-domain, spatially-resolved, nonlinear, and multidimensional spectroscopies. The conference highlights both the application of these techniques in chemistry, materials, biology, the environment, and medicine as well as the development of theoretical models that enable one to connect spectroscopic signatures to underlying molecular motions including chemical reaction dynamics. The conference goal is to advance the field of vibrational spectroscopy by bringing together a collection of researchers who share common interests and who will gain from discussing work at the forefront of several connected areas. The intent is to emphasize the insights and understanding that studies of vibrations provide about a variety of molecular systems ranging from small polyatomic molecules to large biomolecules, nanomaterials, and environmental systems.

  13. Synchrotron Radiation Circular Dichroism (SRCD) Spectroscopy - An Enhanced Method for Examining Protein Conformations and Protein Interactions

    SciTech Connect (OSTI)

    B Wallace; R Janes

    2011-12-31

    CD (circular dichroism) spectroscopy is a well-established technique in structural biology. SRCD (synchrotron radiation circular dichroism) spectroscopy extends the utility and applications of conventional CD spectroscopy (using laboratory-based instruments) because the high flux of a synchrotron enables collection of data at lower wavelengths (resulting in higher information content), detection of spectra with higher signal-to-noise levels and measurements in the presence of absorbing components (buffers, salts, lipids and detergents). SRCD spectroscopy can provide important static and dynamic structural information on proteins in solution, including secondary structures of intact proteins and their domains, protein stability, the differences between wild-type and mutant proteins, the identification of natively disordered regions in proteins, and the dynamic processes of protein folding and membrane insertion and the kinetics of enzyme reactions. It has also been used to effectively study protein interactions, including protein-protein complex formation involving either induced-fit or rigid-body mechanisms, and protein-lipid complexes. A new web-based bioinformatics resource, the Protein Circular Dichroism Data Bank (PCDDB), has been created which enables archiving, access and analyses of CD and SRCD spectra and supporting metadata, now making this information publicly available. To summarize, the developing method of SRCD spectroscopy has the potential for playing an important role in new types of studies of protein conformations and their complexes.

  14. Elemental content of enamel and dentin after bleaching of teeth (a comparative study between laser-induced breakdown spectroscopy and x-ray photoelectron spectroscopy)

    SciTech Connect (OSTI)

    Imam, H.; Ahmed, Doaa; Eldakrouri, Ashraf; Department of Optometry and Vision Science, College of Applied Medical Science, King Saud University, Riyadh

    2013-06-21

    The elemental content of the superficial and inner enamel as well as that of dentin was analyzed using laser-induced breakdown spectroscopy (LIBS) and x-ray photoelectron spectroscopy (XPS) of bleached and unbleached tooth specimens. It is thus clear from the spectral analysis using both the LIBS and XPS technique that elemental changes (though insignificant within the scopes of this study) of variable intensities do occur on the surface of the enamel and extend deeper to reach dentin. The results of the LIBS revealed a slight reduction in the calcium levels in the bleached compared to the control specimens in all the different bleaching groups and in both enamel and dentin. The good correlation found between the LIBS and XPS results demonstrates the possibility of LIBS technique for detection of minor loss in calcium and phosphorus in enamel and dentin.

  15. Applications of Admittance Spectroscopy in Photovoltaic Devices Beyond Majority Carrier Trapping Defects: Preprint

    SciTech Connect (OSTI)

    Li, J. V.; Crandall, R. S.; Repins, I. L.; Nardes, A. M.; Levi, D. H.; Sulima, O.

    2011-07-01

    Admittance spectroscopy is commonly used to characterize majority-carrier trapping defects. In today's practical photovoltaic devices, however, a number of other physical mechanisms may contribute to the admittance measurement and interfere with the data interpretation. Such challenges arise due to the violation of basic assumptions of conventional admittance spectroscopy such as single-junction, ohmic contact, highly conductive absorbers, and measurement in reverse bias. We exploit such violations to devise admittance spectroscopy-based methods for studying the respective origins of 'interference': majority-carrier mobility, non-ohmic contact potential barrier, minority-carrier inversion at hetero-interface, and minority-carrier lifetime in a device environment. These methods are applied to a variety of photovoltaic technologies: CdTe, Cu(In,Ga)Se2, Si HIT cells, and organic photovoltaic materials.

  16. Using laser absorption spectroscopy to monitor composition and physical properties of metal vapors

    SciTech Connect (OSTI)

    Berzins, L.V.

    1993-09-03

    The Atomic Vapor Laser Isotope Separation (AVLIS) program has been using laser absorption spectroscopy to monitor vapor densities for over 15 years. Laser absorption spectroscopy has proven itself to be an accurate and reliable method to monitor both density and composition. During this time the diagnostic has moved from a research tool toward a robust component of a process control system. The hardware used for this diagnostic is discussed elsewhere at this symposium. This paper describes how the laser absorption spectroscopy diagnostic is used as a component of a process control system as well as supplying detailed measurements on vapor densities, composition, flow velocity, internal and kinetic temperatures, and constituent distributions. Examples will be drawn from the uranium AVLIS program. In addition potential applications such as composition control in the production of metal matrix composites or aircraft alloys will be discussed.

  17. Polarized micro Raman scattering spectroscopy for curved edges of epitaxial graphene

    SciTech Connect (OSTI)

    Islam, Md. Sherajul Makino, T.; Hashimoto, A.; Bhuiyan, A. G.; Tanaka, S.

    2014-12-15

    This letter performed polarized microscopic laser Raman scattering spectroscopy on the curved edges of transferred epitaxial graphene on SiO{sub 2}/Si. The intensity ratio between the parallel and perpendicular polarized D band is evolved, providing a spectroscopy-based technique to probe the atomic-scale edge structures in graphene. A detailed analysis procedure for non-ideal disordered curved edges of graphene is developed combining the atomic-scale zigzag and armchair edge structures along with some point defects. These results could provide valuable information of the realistic edges of graphene at the atomic-scale that can strongly influence the performance of graphene-based nanodevices.

  18. Milestones in EBIT Spectroscopy and Why it Almost Didn't Work

    SciTech Connect (OSTI)

    Marrs, R E

    2007-07-17

    The EBIT spectroscopy that now seems routine would not be possible without considerable good luck in several areas of EBIT technology. Among these are x-ray background, ion cooling, neutral gas density, and electron current density and energy control. A favourable outcome in these areas has enabled clean x-ray spectra, sufficient intensity for high resolution spectroscopy, production of very high charge states, and a remarkable variety of spectroscopic measurements. During construction of the first EBIT 20 years ago, it was not clear that any of this was possible.

  19. Raman-Ramsey multizone spectroscopy in a pure rubidium vapor cell

    SciTech Connect (OSTI)

    Failache, H.; Lenci, L.; Lezama, A. [Instituto de Fisica, Facultad de Ingenieria, Universidad de la Republica, 11300 Montevideo (Uruguay)

    2010-02-15

    In view of application to a miniaturized spectroscopy system, we consider an optical setup that splits a laser beam into several parallel narrow light sheets allowing an effective beam expansion and consequently longer atom-light interaction times. We analyze the multizone coherent population trapping (MZCPT) spectroscopy of alkali-metal-vapor atoms, without buffer gas, in the presence of a split light beam. We show that the MZCPT signal is largely insensitive to intensity broadening. Experimentally observed spectra are in qualitative agreement with the predictions of a simplified model that describes each spectrum as an integral over the atomic velocity distribution of Ramsey multizone spectra.

  20. Improving Ramsey spectroscopy in the extreme-ultraviolet region with a random-sampling approach

    SciTech Connect (OSTI)

    Eramo, R.; Bellini, M. [Istituto Nazionale di Ottica (INO-CNR), Largo E. Fermi 6, I-50125 Florence (Italy); European Laboratory for Non-linear Spectroscopy (LENS), I-50019 Sesto Fiorentino, Florence (Italy); Corsi, C.; Liontos, I. [European Laboratory for Non-linear Spectroscopy (LENS), I-50019 Sesto Fiorentino, Florence (Italy); Cavalieri, S. [European Laboratory for Non-linear Spectroscopy (LENS), I-50019 Sesto Fiorentino, Florence (Italy); Department of Physics, University of Florence, I-50019 Sesto Fiorentino, Florence (Italy)

    2011-04-15

    Ramsey-like techniques, based on the coherent excitation of a sample by delayed and phase-correlated pulses, are promising tools for high-precision spectroscopic tests of QED in the extreme-ultraviolet (xuv) spectral region, but currently suffer experimental limitations related to long acquisition times and critical stability issues. Here we propose a random subsampling approach to Ramsey spectroscopy that, by allowing experimentalists to reach a given spectral resolution goal in a fraction of the usual acquisition time, leads to substantial improvements in high-resolution spectroscopy and may open the way to a widespread application of Ramsey-like techniques to precision measurements in the xuv spectral region.

  1. Ultrafast spectroscopy of super high frequency mechanical modes of doubly clamped beams

    SciTech Connect (OSTI)

    Ristow, Oliver; Merklein, Moritz; Grossmann, Martin; Hettich, Mike; Schubert, Martin; Bruchhausen, Axel; Scheer, Elke; Dekorsy, Thomas; Barretto, Elaine C. S.; Grebing, Jochen; Erbe, Artur; Mounier, Denis; Gusev, Vitalyi

    2013-12-02

    We use ultrafast pump-probe spectroscopy to study the mechanical vibrations in the time domain of doubly clamped silicon nitride beams. Beams with two different clamping conditions are investigated. Finite element method calculations are performed to analyse the mode spectra of both structures. By calculating the strain integral on the surface of the resonators, we are able to reproduce the effect of the detection mechanism and identify all the measured modes. We show that our spectroscopy technique combined with our modelling tools allow the investigation of several different modes in the super high frequency range (3-30?GHz) and above, bringing more information about the vibration modes of nanomechanical resonators.

  2. Vertical dispersion methods in x-ray spectroscopy of high temperature plasmas

    SciTech Connect (OSTI)

    Renner, O.; Missalla, T.; Foerster, E.

    1995-12-31

    General formulae for the applying the vertical dispersion principle in x-ray spectroscopy of multiple charged ions are summarized, the characteristics of the experimental schemes based on flat and bent crystals are discussed. The unique properties of the novel spectroscopic methods, i.e., their extremely high dispersion, high spectral and 1-D spatial resolution and good collection efficiency, make them very attractive for ultrahigh-resolution spectroscopy. The examples of successful use of the vertical dispersion modifications of the double-crystal and the Johann spectrometer in diagnostics of several types of laser-generated plasma are presented.

  3. Photo-degradation of Lexan polycarbonate studied using positron lifetime spectroscopy

    SciTech Connect (OSTI)

    Hareesh, K.; Sanjeev, Ganesh; Pandey, A. K.; Meghala, D.; Ranganathaiah, C.

    2013-02-05

    The free volume properties of pristine and UV irradiated Lexan polycarbonate have been investigated using Positron Lifetime Spectroscopy (PLS). The decrease in o-Ps life time and free volume size of irradiated sample is attributed to free volume modification and formation of more stable free radicals. These free radicals are formed due to the breakage of C-O bonds in Lexan polycarbonate after irradiation. This is also supported by the decrease in the intensity of C-O bond after exposure to UV-radiation as studied from Fourier Transform Infrared (FTIR) spectroscopy and it also shows that benzene ring does not undergo any changes after irradiation.

  4. The X-ray correlation spectroscopy instrument at the Linac Coherent Light Source

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Alonso-Mori, Roberto; Caronna, Chiara; Chollet, Matthieu; Curtis, Robin; Damiani, Daniel S.; Defever, Jim; Feng, Yiping; Flath, Daniel L.; Glownia, James M.; Lee, Sooheyong; et al

    2015-03-03

    The X-ray Correlation Spectroscopy instrument is dedicated to the study of dynamics in condensed matter systems using the unique coherence properties of free-electron lasers. It covers a photon energy range of 4–25 keV. The intrinsic temporal characteristics of the Linac Coherent Light Source, in particular the 120 Hz repetition rate, allow for the investigation of slow dynamics (milliseconds) by means of X-ray photon correlation spectroscopy. Double-pulse schemes could probe dynamics on the picosecond timescale. In addition, a description of the instrument capabilities and recent achievements is presented.

  5. Radiative Bottomonium Spectroscopy at the Y(2, 3S) Resonances at BaBar

    Office of Scientific and Technical Information (OSTI)

    (Thesis/Dissertation) | SciTech Connect Radiative Bottomonium Spectroscopy at the Y(2, 3S) Resonances at BaBar Citation Details In-Document Search Title: Radiative Bottomonium Spectroscopy at the Y(2, 3S) Resonances at BaBar Authors: Lewis, Peter M. ; /Stanford U., Phys. Dept. /SLAC Publication Date: 2013-08-26 OSTI Identifier: 1091526 Report Number(s): SLAC-R-1035 DOE Contract Number: AC02-76SF00515 Resource Type: Thesis/Dissertation Research Org: SLAC National Accelerator Laboratory (SLAC)

  6. Recent Results on Meson Spectroscopy from BELLE And BaBar (Journal Article)

    Office of Scientific and Technical Information (OSTI)

    | SciTech Connect Journal Article: Recent Results on Meson Spectroscopy from BELLE And BaBar Citation Details In-Document Search Title: Recent Results on Meson Spectroscopy from BELLE And BaBar Authors: Uehara, Sadaharu ; /KEK, Tsukuba Publication Date: 2013-05-31 OSTI Identifier: 1081533 Report Number(s): SLAC-REPRINT-2013-079 DOE Contract Number: AC02-76SF00515 Resource Type: Journal Article Resource Relation: Journal Name: Int.J.Mod.Phys.A26:341-346,2011 Research Org: SLAC National

  7. In Operando Soft X-ray Spectroscopy of 3D Graphene Supercapacitor

    Office of Scientific and Technical Information (OSTI)

    Electrodes (Journal Article) | SciTech Connect In Operando Soft X-ray Spectroscopy of 3D Graphene Supercapacitor Electrodes Citation Details In-Document Search Title: In Operando Soft X-ray Spectroscopy of 3D Graphene Supercapacitor Electrodes Authors: Bagge-Hansen, M ; Wood, B C ; Ogitsu, T ; Willey, T M ; Tran, I C ; Wittstock, A ; Biener, M M ; Merrill, M D ; Worsley, M A ; Otani, M ; Chuang, C H ; Prendergast, D ; Guo, J ; Baumann, T F ; van Buuren, T ; Biener, J ; Lee, J I Publication

  8. Interband magneto-spectroscopy in InSb square and parabolic quantum wells

    Office of Scientific and Technical Information (OSTI)

    (Journal Article) | SciTech Connect Interband magneto-spectroscopy in InSb square and parabolic quantum wells Citation Details In-Document Search Title: Interband magneto-spectroscopy in InSb square and parabolic quantum wells We measure the magneto-optical absorption due to intersubband optical transitions between conduction and valence subband Landau levels in InSb square and parabolic quantum wells. InSb has the narrowest band gap (0.24 eV at low temperature) of the III-V semiconductors

  9. Depth Profiling of SiC Lattice Damage Using Micro-Raman Spectroscopy

    Office of Scientific and Technical Information (OSTI)

    (Conference) | SciTech Connect Depth Profiling of SiC Lattice Damage Using Micro-Raman Spectroscopy Citation Details In-Document Search Title: Depth Profiling of SiC Lattice Damage Using Micro-Raman Spectroscopy Depth profiling for the amount of lattice damage using a Confocal Micro-Raman (CMR) spectrometer is demonstrated in this paper. Samples of n-type silicon carbide were implanted with 2 MeV He and O ions at both room temperature and 500 C, and fluences between 10{sup 15} and 10{sup 17}

  10. Excited-state spectroscopy of singly, doubly and triply-charmed baryons

    Office of Scientific and Technical Information (OSTI)

    from lattice QCD (Conference) | SciTech Connect Conference: Excited-state spectroscopy of singly, doubly and triply-charmed baryons from lattice QCD Citation Details In-Document Search Title: Excited-state spectroscopy of singly, doubly and triply-charmed baryons from lattice QCD We present the ground and excited state spectra of singly, doubly and triply-charmed baryons by using dynamical lattice QCD. A large set of baryonic operators that respect the symmetries of the lattice and are

  11. Exotic/charmonium Hadron Spectroscopy at Belle and BaBar (Conference) |

    Office of Scientific and Technical Information (OSTI)

    SciTech Connect Conference: Exotic/charmonium Hadron Spectroscopy at Belle and BaBar Citation Details In-Document Search Title: Exotic/charmonium Hadron Spectroscopy at Belle and BaBar Authors: Liventsev, Dmitri ; /Moscow, ITEP ; Publication Date: 2013-10-14 OSTI Identifier: 1096828 Report Number(s): SLAC-PUB-15785 arXiv:1105.4760 DOE Contract Number: AC02-76SF00515 Resource Type: Conference Resource Relation: Journal Name: arXiv:1105.4760; Conference: Prepared for 46th Rencontres de Moriond

  12. A new spectrometer design for the x-ray spectroscopy of laser-produced

    Office of Scientific and Technical Information (OSTI)

    plasmas with high (sub-ns) time resolution (Journal Article) | SciTech Connect A new spectrometer design for the x-ray spectroscopy of laser-produced plasmas with high (sub-ns) time resolution Citation Details In-Document Search Title: A new spectrometer design for the x-ray spectroscopy of laser-produced plasmas with high (sub-ns) time resolution This paper describes a new type of x-ray crystal spectrometer, which can be used in combination with gated x-ray detectors to obtain spectra from

  13. Bottomonium Spectroscopy at BaBar and Belle (Conference) | SciTech Connect

    Office of Scientific and Technical Information (OSTI)

    Conference: Bottomonium Spectroscopy at BaBar and Belle Citation Details In-Document Search Title: Bottomonium Spectroscopy at BaBar and Belle Authors: Simi, Gabriele ; /Maryland U. Publication Date: 2013-06-12 OSTI Identifier: 1083513 Report Number(s): SLAC-PUB-15563 DOE Contract Number: AC02-76SF00515 Resource Type: Conference Resource Relation: Journal Name: PoS BEAUTY2009:036,2009; Conference: Prepared for 12th International Conference on B Physics at Hadron Machines (BEAUTY 2009),

  14. Hollow Core Fiber Optics for Mid-Wave and Long-Wave Infrared Spectroscopy

    SciTech Connect (OSTI)

    Kriesel, J.M.; Gat, N.; Bernacki, Bruce E.; Erikson, Rebecca L.; Cannon, Bret D.; Myers, Tanya L.; Bledt, Carlos M.; Harrington, J. A.

    2011-06-01

    The development and testing of hollow core glass waveguides (i.e., fiber optics) for use in Long-Wave Infrared (LWIR) spectroscopy systems is described. LWIR fiber optics are a key enabling technology needed to improve the utility and effectiveness of trace chemical detection systems based in the 8 to 12 micron region. This paper focuses on recent developments in hollow waveguide technology geared specifically for LWIR spectroscopy, including a reduction in both the length dependent loss and the bending loss while maintaining relatively high beam quality. Results will be presented from tests conducted with a Quantum Cascade Laser.

  15. COLLOQUIUM: Development of High Resolution X-Ray Spectroscopy at PPPL |

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Princeton Plasma Physics Lab January 21, 2015, 4:00pm to 5:30pm Colloquia MBG Auditorium COLLOQUIUM: Development of High Resolution X-Ray Spectroscopy at PPPL Dr. Kenneth Hill Princeton Plasma Physics Laboratory This lecture reviews the development of x-ray spectroscopy at PPPL, which began in the 1970's on the ST (Symmetric Tokamak) and has had a significant impact on the magnetic fusion research program worldwide. Several important physics parameters can be measured with these techniques.

  16. Gas cell for in situ soft X-ray transmission-absorption spectroscopy of

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    materials | Center for Gas SeparationsRelevant to Clean Energy Technologies | Blandine Jerome cell for in situ soft X-ray transmission-absorption spectroscopy of materials Previous Next List W. S. Drisdell and J. B. Kortright, Rev. Sci. Instrum. 85, 074103 (2014) DOI: 10.1063/1.4890816 1.4890816.figures.online.f1 Abstract: A simple gas cell design, constructed primarily from commercially available components, enables in situ soft X-ray transmission-absorption spectroscopy of materials in

  17. Spectroscopy of Ba and Ba + deposits in solid xenon for barium tagging in

    Office of Scientific and Technical Information (OSTI)

    nEXO (Journal Article) | SciTech Connect Spectroscopy of Ba and Ba + deposits in solid xenon for barium tagging in nEXO Citation Details In-Document Search Title: Spectroscopy of Ba and Ba + deposits in solid xenon for barium tagging in nEXO Authors: Mong, B. ; Cook, S. ; Walton, T. ; Chambers, C. ; Craycraft, A. ; Benitez-Medina, C. ; Hall, K. ; Fairbank, W. ; Albert, J. B. ; Auty, D. J. ; Barbeau, P. S. ; Basque, V. ; Beck, D. ; Breidenbach, M. ; Brunner, T. ; Cao, G. F. ; Cleveland, B. ;

  18. X-Ray Spectroscopy of the Mn(4) Ca Cluster in the Water-Oxidation Complex

    Office of Scientific and Technical Information (OSTI)

    of Photosystem II (Journal Article) | SciTech Connect X-Ray Spectroscopy of the Mn(4) Ca Cluster in the Water-Oxidation Complex of Photosystem II Citation Details In-Document Search Title: X-Ray Spectroscopy of the Mn(4) Ca Cluster in the Water-Oxidation Complex of Photosystem II No abstract prepared. Authors: Sauer, K. ; Yano, J. ; Yachandra, V.K. ; /UC, Berkeley /LBL, Berkeley Publication Date: 2007-08-08 OSTI Identifier: 912555 Report Number(s): SLAC-REPRINT-2005-323 TRN: US200801%%922

  19. X-ray line polarization spectroscopy of Li-like satellite line spectra

    Office of Scientific and Technical Information (OSTI)

    (Journal Article) | SciTech Connect Journal Article: X-ray line polarization spectroscopy of Li-like satellite line spectra Citation Details In-Document Search Title: X-ray line polarization spectroscopy of Li-like satellite line spectra We apply the magnetic-sublevel atomic kinetics model POLAR to the calculation of polarization properties of satellite lines in Li-like Si driven by subpicosecond-duration laser pulses. We identify spectral lines whose polarization can serve as a marker of

  20. Decoupling Bulk and Surface Contributions in Water- Splitting Photocatalysts by In Situ Ultrafast Spectroscopy

    SciTech Connect (OSTI)

    Appavoo, Kannatassen; Mingzhao, Liu; Black, Charles T.; Sfeir, Matthew Y.

    2015-05-10

    By performing ultrafast emission spectroscopy in an operating, bias-controlled photoelectrochemical cell, we distinguish between bulk (charge transport) and surface (chemical reaction) recombination processes in a nanostructured photocatalyst and correlate its electronic properties directly with its incident-photon-to-current efficiency.