National Library of Energy BETA

Sample records for angle-resolved photoemission spectroscopy

  1. Substrate interactions with suspended and supported monolayer MoS?: Angle-resolved photoemission spectroscopy

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

    Jin, Wencan; Sadowski, Jerzy T.; Yeh, Po-Chun; Zaki, Nader; Zhang, Datong; Liou, Jonathan T.; Dadap, Jerry I.; Herman, Irving P.; Osgood, Jr., Richard M.; Sutter, Peter; et al

    2015-03-17

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

  2. 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 (MoS?) using micrometer-scale angle-resolved photoemission spectroscopy. Measurements of both suspended and supported monolayer MoS? 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 MoS? crystals. For suspended MoS?, a careful investigation of the measured uppermost valence band gives an effective mass at ?¯ and ?¯ of 2.00m? and 0.43m?, respectively. We also measure an increase in the band linewidth from the midpoint of ?¯?¯ to the vicinity of ?¯ and briefly discussmore »its possible origin.« less

  3. Tunable vacuum ultraviolet laser based spectrometer for angle resolved photoemission spectroscopy

    SciTech Connect (OSTI)

    Jiang, Rui; Mou, Daixiang; Wu, Yun; Huang, Lunan; Kaminski, Adam [Division of Materials Science and Engineering, Ames Laboratory, Ames, Iowa 50011 (United States) [Division of Materials Science and Engineering, Ames Laboratory, Ames, Iowa 50011 (United States); Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011 (United States); McMillen, Colin D.; Kolis, Joseph [Department of Chemistry, Clemson University, Clemson, South Carolina 29634 (United States)] [Department of Chemistry, Clemson University, Clemson, South Carolina 29634 (United States); Giesber, Henry G.; Egan, John J. [Advanced Photonic Crystals LLC, Fort Mill, South Carolina 29708 (United States)] [Advanced Photonic Crystals LLC, Fort Mill, South Carolina 29708 (United States)

    2014-03-15

    We have developed an angle-resolved photoemission spectrometer with tunable vacuum ultraviolet laser as a photon source. The photon source is based on the fourth harmonic generation of a near IR beam from a Ti:sapphire laser pumped by a CW green laser and tunable between 5.3 eV and 7 eV. The most important part of the set-up is a compact, vacuum enclosed fourth harmonic generator based on potassium beryllium fluoroborate crystals, grown hydrothermally in the US. This source can deliver a photon flux of over 10{sup 14} photon/s. We demonstrate that this energy range is sufficient to measure the k{sub z} dispersion in an iron arsenic high temperature superconductor, which was previously only possible at synchrotron facilities.

  4. Angle-Resolved Photoemission Spectroscopy on Electronic Structure and Electron-Phonon Coupling in Cuprate Superconductors

    SciTech Connect (OSTI)

    Zhou, X.J.

    2010-04-30

    In addition to the record high superconducting transition temperature (T{sub c}), high temperature cuprate superconductors are characterized by their unusual superconducting properties below T{sub c}, and anomalous normal state properties above T{sub c}. In the superconducting state, although it has long been realized that superconductivity still involves Cooper pairs, as in the traditional BCS theory, the experimentally determined d-wave pairing is different from the usual s-wave pairing found in conventional superconductors. The identification of the pairing mechanism in cuprate superconductors remains an outstanding issue. The normal state properties, particularly in the underdoped region, have been found to be at odd with conventional metals which is usually described by Fermi liquid theory; instead, the normal state at optimal doping fits better with the marginal Fermi liquid phenomenology. Most notable is the observation of the pseudogap state in the underdoped region above T{sub c}. As in other strongly correlated electrons systems, these unusual properties stem from the interplay between electronic, magnetic, lattice and orbital degrees of freedom. Understanding the microscopic process involved in these materials and the interaction of electrons with other entities is essential to understand the mechanism of high temperature superconductivity. Since the discovery of high-T{sub c} superconductivity in cuprates, angle-resolved photoemission spectroscopy (ARPES) has provided key experimental insights in revealing the electronic structure of high temperature superconductors. These include, among others, the earliest identification of dispersion and a large Fermi surface, an anisotropic superconducting gap suggestive of a d-wave order parameter, and an observation of the pseudogap in underdoped samples. In the mean time, this technique itself has experienced a dramatic improvement in its energy and momentum resolutions, leading to a series of new discoveries not thought possible only a decade ago. This revolution of the ARPES technique and its scientific impact result from dramatic advances in four essential components: instrumental resolution and efficiency, sample manipulation, high quality samples and well-matched scientific issues. The purpose of this treatise is to go through the prominent results obtained from ARPES on cuprate superconductors. Because there have been a number of recent reviews on the electronic structures of high-T{sub c} materials, we will mainly present the latest results not covered previously, with a special attention given on the electron-phonon interaction in cuprate superconductors. What has emerged is rich information about the anomalous electron-phonon interaction well beyond the traditional views of the subject. It exhibits strong doping, momentum and phonon symmetry dependence, and shows complex interplay with the strong electron-electron interaction in these materials. ARPES experiments have been instrumental in identifying the electronic structure, observing and detailing the electron-phonon mode coupling behavior, and mapping the doping evolution of the high-T{sub c} cuprates. The spectra evolve from the strongly coupled, polaronic spectra seen in underdoped cuprates to the Migdal-Eliashberg like spectra seen in the optimally and overdoped cuprates. In addition to the marked doping dependence, the cuprates exhibit pronounced anisotropy with direction in the Brillouin zone: sharp quasiparticles along the nodal direction that broaden significantly in the anti-nodal region of the underdoped cuprates, an anisotropic electron-phonon coupling vertex for particular modes identified in the optimal and overdoped compounds, and preferential scattering across the two parallel pieces of Fermi surface in the antinodal region for all doping levels. This also contributes to the pseudogap effect. To the extent that the Migdal-Eliashberg picture applies, the spectra of the cuprates bear resemblance to that seen in established strongly coupled electron-phonon superconductors such as Pb. On the other

  5. 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...

  6. 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 Fermimore »sheets, 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

  7. 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, 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 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

  8. Revealing Charge Density Wave Formation in the LaTe2 System byAngle Resolved Photoemission Spectroscopy

    SciTech Connect (OSTI)

    Garcia, D.R.; Gweon, G.-H.; Zhou, S.Y.; Graf, J.; Jozwiak, C.M.; Jung, M.H.; Kwon, Y.S.; Lanzara, A.

    2006-11-15

    We present the first direct study of charge density wave(CDW) formation in quasi-2D single layer LaTe2 using high-resolutionangle resolved photoemission spectroscopy (ARPES) and low energy electrondiffraction (LEED). CDW formation is driven by Fermi surface (FS)nesting, however characterized by a surprisingly smaller gap (~;50 meV)than seen in the double layer RTe3 compounds, extending over the entireFS. This establishes LaTe2 as the first reported semiconducting 2D CDWsystem where the CDW phase is FS nesting driven. In addition, the layerdependence of this phase in the tellurides and the possible transitionfrom a stripe to a checkerboard phase is discussed.

  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. 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.

  11. High Resolution Angle Resolved Photoemission with Tabletop 11eV Laser

    E-Print Network [OSTI]

    He, Yu; Yi, Ming; Yang, Shuolong; Liu, Zhongkai; Lee, James; Chen, Sudi; Rebec, Slavko; Leuenberger, Dominik; Zong, Alfred; Jefferson, Michael; Moore, Robert; Kirchmann, Patrick; Merriam, Andrew; Shen, Zhixun

    2015-01-01

    We developed a table-top vacuum ultraviolet (VUV) laser with $113.778$nm wavelength (10.897eV) and demonstrated its viability as a photon source for high resolution angle-resolved photoemission spectroscopy (ARPES). This sub-nanosecond pulsed VUV laser operates at a repetition rate of 10MHz, provides a flux of 2$\\times$10$^{12}$ photons/second, and enables photoemission with energy and momentum resolutions better than 2meV and 0.012\\AA$^{-1}$, respectively. Space-charge induced energy shifts and spectral broadenings can be reduced below 2meV. The setup reaches electron momenta up to 1.2\\AA$^{-1}$, granting full access to the first Brillouin zone of most materials. Control over the linear polarization, repetition rate, and photon flux of the VUV source facilitates ARPES investigations of a broad range of quantum materials, bridging the application gap between contemporary low energy laser-based ARPES and synchrotron-based ARPES. We describe the principles and operational characteristics of this source, and sho...

  12. Direct observation of spin-polarized surface states in the parent compound of a topological insulator using spin- and angle-resolved photoemission spectroscopy in a Mott-polarimetry mode

    E-Print Network [OSTI]

    Hsieh, David

    We report high-resolution spin-resolved photoemission spectroscopy (spin-ARPES) measurements on the parent compound Sb of the recently discovered three-dimensional topological insulator Bi1?xSbx (Hsieh et al 2008 Nature ...

  13. 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.

  14. Nodal Quasiparticle Meltdown in Ultra-High Resolution Pump-Probe Angle-Resolved Photoemission

    SciTech Connect (OSTI)

    Graf, Jeff; Jozwiak, Chris; Smallwood, Chris L.; Eisaki, H.; Kaindl, Robert A.; Lee, Dung-Hai; Lanzara, Alessandra

    2011-06-03

    High-T{sub c} cuprate superconductors are characterized by a strong momentum-dependent anisotropy between the low energy excitations along the Brillouin zone diagonal (nodal direction) and those along the Brillouin zone face (antinodal direction). Most obvious is the d-wave superconducting gap, with the largest magnitude found in the antinodal direction and no gap in the nodal direction. Additionally, while antin- odal quasiparticle excitations appear only below T{sub c}, superconductivity is thought to be indifferent to nodal excitations as they are regarded robust and insensitive to T{sub c}. Here we reveal an unexpected tie between nodal quasiparticles and superconductivity using high resolution time- and angle-resolved photoemission on optimally doped Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8+{delta}}#14;. We observe a suppression of the nodal quasiparticle spectral weight following pump laser excitation and measure its recovery dynamics. This suppression is dramatically enhanced in the superconducting state. These results reduce the nodal-antinodal dichotomy and challenge the conventional view of nodal excitation neutrality in superconductivity. The electronic structures of high-Tc cuprates are strongly momentum-dependent. This is one reason why the momentum-resolved technique of angle-resolved photoemission spectroscopy (ARPES) has been a central tool in the #12;field of high-temperature superconductivity. For example, coherent low energy excitations with momenta near the Brillouin zone face, or antinodal quasiparticles (QPs), are only observed below T{sub c} and have been linked to superfluid density. They have therefore been the primary focus of ARPES studies. In contrast, nodal QPs, with momenta along the Brillouin zone diagonal, have received less attention and are usually regarded as largely immune to the superconducting transition because they seem insensitive to perturbations such as disorder, doping, isotope exchange, charge ordering, and temperature. Clearly, finding any strong dependencies of the nodal QPs will alter the conventional view and enrich our understanding of high temperature superconductivity. Time resolution through pump-and-probe techniques adds a new dimension to ARPES by directly measuring how the electronic structure of a material responds to perturbations on femtosecond time scales. Here we report a unique ultrafast time-resolved ARPES study of a high-T{sub c} cuprate superconductor. Compared to previous time-resolved studies, the primary advantage of this work is an unprecedented momentum (angular) resolution ({Delta}#1;k~ #24;0.003 vs. 0.05 {#23;Angstrom}{sup -1}), on par with that of state-of-the-art ARPES. This has allowed the time-resolved measurement of signi#12;cantly sharper QP spectral peaks with strikingly larger peak-to-background ratios than previously reported.16 Additionally, a lower pump fluence is used (<40{micro}#22;J/cm{sup 2} vs. #24;100#22;{micro}J/cm{sup 2}), which reduces pump-induced sample temperature increase and related thermal smearing of spectral features. This allows us to uncover a surprising meltdown of nodal QP spectral weight following pump laser excitation. This meltdown is only observed in the superconducting state and for QPs with binding energy less than the kink energy,19 revealing a link between nodal QPs and superconductivity.

  15. Integrated experimental setup for angle resolved photoemission spectroscopy

    Office of Scientific and Technical Information (OSTI)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfate Reducing(Journal Article)lasers(JournalatBaBartheExpansion (Journal Article) |Report)Crystalsof

  16. 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.

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

    Office of Scientific and Technical Information (OSTI)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfate Reducing(Journal Article)lasers (Journal Article)SciTechHigh-contrast imaging|spectroscopy

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

    Office of Scientific and Technical Information (OSTI)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefield MunicipalTechnicalInformation4563AbuseConnect Technicalofand PuConnectinArticle)

  19. 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...

  20. Photoemission Spectroscopy at SRI2013

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration wouldMass mapSpeeding access| DepartmentPeerFederal FleetUp in the Air PhotoPhotoemission

  1. Validation of angle-resolved polarized light scattering spectroscopy as a diagnostic tool for pre-cancer detection

    E-Print Network [OSTI]

    Kalashnikov, Maxim M

    2009-01-01

    Light scattering spectroscopy has emerged as a valuable diagnostic tool for cancer diagnoses in the past ten years. The interaction of light with cellular structures brings out information about morphological changes ...

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

    Office of Scientific and Technical Information (OSTI)

    and Applications Division, Condensed Matter and Magnet Science Group, Los Alamos, New Mexico 87544 (United States) Los Alamos National Laboratory, Materials Physics and...

  3. Revealing Charge Density Wave Formation in the LaTe2 System by Angle Resolved Photoemission Spectroscopy

    E-Print Network [OSTI]

    2006-01-01

    energy electron di?raction (LEED). CDW formation is driven1D CDW materials. ARPES and LEED data were taken on LaTe 2by TEM, Fig. 4a shows LEED taken on the sample surface. As

  4. Note: Low energy inverse photoemission spectroscopy apparatus

    SciTech Connect (OSTI)

    Yoshida, Hiroyuki, E-mail: yoshida@e.kuicr.kyoto-u.ac.jp [Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011 (Japan)] [Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011 (Japan)

    2014-01-15

    An apparatus for the low-energy inverse photoemission spectroscopy is described. In this technique, low energy electron having kinetic energy below 4 eV is incident to the sample and detect the emitted photons in the near ultraviolet range (below 5 eV, longer than 250 nm) to investigate the unoccupied states of the solid materials. Compared with the prototype apparatus reported previously [H. Yoshida, Chem. Phys. Lett. 539–540, 180–185 (2012)], the collection efficiency of photons is improved by a factor of four and practically any conductive substrates can be used. The overall resolution is 0.27 eV.

  5. Angle-Resolved Photoemission Studies of Quantum Materials (Journal Article)

    Office of Scientific and Technical Information (OSTI)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefield MunicipalTechnicalInformation4563AbuseConnect Technicalofand PuConnectinArticle) |Coloured|

  6. 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.

  7. Near E{sub F} Electronic Structure of Graphite from Photoemission and Inverse Photoemission Studies

    SciTech Connect (OSTI)

    Sekhar, B. R.; Kundu, R.; Mishra, P. [Institute of Physics, Sachivalaya Marg, Bhubaneswar 751005 (India); Maniraj, M.; Barman, S. R. [Surface Physics Laboratory, UGC-DAE Consortium for Scientific Research, Khandwa Road, Indore 452001, Madhya Pradesh (India)

    2011-10-20

    A comparative study of the electronic band structure of single crystal and highly oriented pyrolitic graphite is presented. We have used angle resolved photoelectron spectroscopy and angle resolved inverse photoelectron spectroscopy to map the occupied and unoccupied electronic states respectively.

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

    Office of Scientific and Technical Information (OSTI)

    ELEMENTARY PARTICLES AND FIELDS; PHOTOEMISSION; SELF-ENERGY; EMISSION SPECTROSCOPY; ELECTRONS; PHONONS Other,OTHER Word Cloud More Like This Full Text Journal Articles DOI:...

  9. 9 Metal to Non-metal Transitions in Solids and on Surfaces studied using Photoemission Spectroscopy

    E-Print Network [OSTI]

    Redner, Sidney

    9 Metal to Non-metal Transitions in Solids and on Surfaces studied using Photoemission Spectroscopy of the electrical properties of a material between those of a metal and those of a non-metal (be it semiconducting metal to non-metal transitions. (Thephrase `metal to non-metal transition' is used in this paper

  10. 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.

  11. Two-photon Photo-emission of Ultrathin Film PTCDA Morphologies on Ag(111)

    E-Print Network [OSTI]

    Yang, Aram

    2008-01-01

    Two-photon Photo-emission of Ultrathin Film PTCDAwith angle-resolved two-photon photo- emission. In Stranski-probe laser pulse, h? 2 , photo-emits the electron. research

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

    Office of Scientific and Technical Information (OSTI)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfate Reducing(Journal Article)lasers (Journal Article)SciTechHigh-contrast imaging|

  13. Spin injection and spin dynamics at the CuPc/GaAs interface studied with ultraviolet photoemission spectroscopy and two-photon photoemission spectroscopy

    E-Print Network [OSTI]

    Aeschlimann, Martin

    injection via Schottky contacts. Only recently, direct electrical spin injec- tion with organicSpin injection and spin dynamics at the CuPc/GaAs interface studied with ultraviolet photoemission show a highly efficient spin injection of hot electrons from GaAs into CuPc, demonstrating that spin

  14. 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.

  15. 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. [Science and Technology on Surface Physics and Chemistry Lab., Mianyang (China); Fundan Univ., Shanghai (China); Jiang, J. [Fundan Univ., Shanghai (China); Nanjing Univ., Nanjing (China); Ye, Z. R. [Fundan Univ., Shanghai (China); Niu, X. H. [Fundan Univ., Shanghai (China); Nanjing Univ., Nanjing (China); Song, Y. [Rice Univ., Houston, TX (United States); Zhang, C. L. [Rice Univ., Houston, TX (United States); Univ. of Tennessee, Knoxville, TN (United States); Dai, P. C. [Rice Univ., Houston, TX (United States); Xie, B. P. [Fundan Univ., Shanghai (China); Nanjing Univ., Nanjing (China); Lai, X. C. [Science and Technology on Surface Physics and Chemistry Lab., Mianyang (China); Feng, D. L. [Fundan Univ., Shanghai (China); Nanjing Univ., Nanjing (China)

    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)

  16. 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 atmore »7 K, indicating that Na?Ti?Sb?O is likely a weakly correlated CDW material in the strong electron-phonon interaction regime. (author)« less

  17. 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.

  18. Prospective grading of neoplastic change in rat esophagus epithelium using angle-resolved low-coherence interferometry

    E-Print Network [OSTI]

    Wax, Adam

    Angle-resolved low-coherence interferometry (a/LCI) is used to obtain quantitative, depth-resolved nuclear morphology measurements. We compare the average diameter and texture of cell nuclei in rat esophagus epithelial ...

  19. 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.

  20. Electronic Charges and Electric Potential at LaAlO3/SrTiO3 Interfaces Studied by Core-Level Photoemission Spectroscopy

    SciTech Connect (OSTI)

    Hwang, Harold

    2011-08-19

    We studied LaAlO{sub 3}/SrTiO{sub 3} interfaces for varying LaAlO{sub 3} thickness by core-level photoemission spectroscopy. In Ti 2p spectra for conducting 'n-type' interfaces, Ti{sup 3+} signals appeared, which were absent for insulating 'p-type' interfaces. The Ti{sup 3+} signals increased with LaAlO{sub 3} thickness, but started well below the critical thickness of 4 unit cells for metallic transport. Core-level shifts with LaAlO{sub 3} thickness were much smaller than predicted by the polar catastrophe model. We attribute these observations to surface defects/adsorbates providing charges to the interface even below the critical thickness.

  1. 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.

  2. Influence of the contact potential and space-charge effect on the performance of a Stoffel-Johnson design electron source for inverse photoemission spectroscopy

    SciTech Connect (OSTI)

    Maniraj, M.; Barman, Sudipta Roy [UGC-DAE Consortium for Scientific Research, Khandwa Road, Indore 452001, Madhya Pradesh (India)] [UGC-DAE Consortium for Scientific Research, Khandwa Road, Indore 452001, Madhya Pradesh (India)

    2014-03-15

    By imaging the spatial intensity distribution of the electrons from a Stoffel-Johnson (SJ) type low energy electron source for inverse photoemission spectroscopy (IPES), we find that the focus is distorted when the beam current exceeds the limiting value due to space charge effect. The space charge effect and the contact potential difference suppress the beam current at low energies (<10 eV). In this work, we show that these limitations of the SJ source can be overcome by compensation of the contact potential difference between the cathode and the lens electrodes and an uniform well focused electron beam with the set kinetic energy can be obtained. The size of the electron beam is around 1 mm full width at half maximum over the whole energy range of 5 to 30 eV generally used for IPES. The compensation of the contact potential difference also enhances the beam current substantially at low energies (<10 eV) and uniform beam current is achieved for the whole energy range. We find that the drift in the electron beam position is sensitive to the lens electrode separation and it is about 1 mm over the whole energy range. By measuring the n = 1 image potential state on Cu(100), we show that the resolution is better when the cathode filament current is set to lower values.

  3. J. Phys.: Condens. Matter 8 (1996) 41894193. Printed in the UK Angle-resolved photoemission of InSb(111)2 2

    E-Print Network [OSTI]

    Kim, Sehun

    1996-01-01

    Abstract. The electronic band structure of InSb(111) along the ­ ­L 111 direction was determined using structures of GaAs(111)­2 × 2 surfaces was also carried out to determine the atomic geometry [7, 8]. However to the surface state and the resonance process of the InSb(111)­2 × 2. Investigations of electronic properties

  4. 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

  5. Electron-State Hybridization in Heavy-Fermion Systems

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

    the subject of extensive debate. An international team of researchers from Germany, Ukraine, India, and the U.S. has performed angle-resolved photoemission spectroscopy (ARPES)...

  6. Superconducting Topological Insulators

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

    some of the most desirable traits for computing components and next-generation "spintronics" technologies. More recent angle-resolved photoemission spectroscopy (ARPES)...

  7. Homegrown solution for synchrotron light source | The Ames Laboratory

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

    called angle-resolved photoemission spectroscopy (ARPES) in which light energy (photons) is directed at a sample being studied. The photons cause electrons in the sample to...

  8. Search for: All records | SciTech Connect

    Office of Scientific and Technical Information (OSTI)

    4 by angle-resolved photoemission spectroscopy. The results clearly exhibit two distinct energy and temperature scales, namely, the gap around (pi, 0) of magnitude Delta* and...

  9. Microsoft Word - Science and Technology of Future Light Sources...

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

    is the dispersion relations of the quasi-particles in these regions. A natural tool is angle-resolved photoemission spectroscopy (ARPES) which has emerged as the mainstream...

  10. Bond stretching phonon softening and angle-resolved photoemission kinks in optimally doped Bi2Sr1:6La0:4Cu2O6+sigma superconductors

    E-Print Network [OSTI]

    Graf, Jeff

    2008-01-01

    La 0.4 Cu 2 O 6+? superconductors J. Graf, 1 M. d’Astuto, 2softening is related to superconductivity or to the strongtransition in cuprates superconductors [1–4, 6, 7] as well

  11. 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.

  12. 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...

  13. Direct observation of a dispersionless impurity band in hydrogenated graphene

    E-Print Network [OSTI]

    Haberer, D.

    We show with angle-resolved photoemission spectroscopy that a new energy band appears in the electronic structure of electron-doped hydrogenated monolayer graphene (H-graphene). Its occupation can be controlled with the ...

  14. A New Spin on Photoemission Spectroscopy

    E-Print Network [OSTI]

    Jozwiak, Chris

    2010-01-01

    18. Wolf, S. A. et al. Spintronics: A Spin-Based Electronicsthe electron spin (spintronics 17,18 ) explicitly relies onand crossed. Applied to spintronics materials and de- vices,

  15. 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.

  16. This content has been downloaded from IOPscience. Please scroll down to see the full text. Download details

    E-Print Network [OSTI]

    Taillefer, Louis

    Thermal conductivity, point contact spectroscopy, angle-resolved photoemission and Raman spectroscopy conductivity was measured in the superconducting state as a function of temperature and magnetic field Andreev reflection spectroscopy measurements were performed as a function of temperature using the needle

  17. Spectroscopy

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach Home RoomPreservation ofAlbuquerque|SensitiveApril 2, 2014 Smith NamedDiversityAquiferSpectroscopy

  18. RAPID COMMUNICATIONS PHYSICAL REVIEW B 87, 180509(R) (2013)

    E-Print Network [OSTI]

    Johnson, Peter D.

    2013-01-01

    .5 Density functional theory calculations6 and angle-resolved photoemission spectroscopy (ARPES)7 quasiparticle dynamics reveal a nanosecond effective recombination time and temperature dependence that strongly penetration depth,10 and point-contact spectroscopy11 mea- surements. Although it has been widely assumed

  19. High-Resolution Synchrotron Photoemission Studies of the Electronic Structure and Thermal Stability of CH3-and C2H5-Functionalized Si(111) Surfaces

    E-Print Network [OSTI]

    Webb, Lauren J.

    can yield only partial termination of the Si(111) surface by Si-C bonds (Figure 1b). X photoemission spectroscopy. Whereas the CH3-terminated Si(111) surface showed only one C 2s peak for the occupied orbitals, the C 2s spectra of C2H5-terminated Si(111) surfaces showed a symmetric splitting

  20. CLNS 03/1827 VERY HIGH VOLTAGE PHOTOEMISSION ELECTRON GUNS*

    E-Print Network [OSTI]

    CLNS 03/1827 VERY HIGH VOLTAGE PHOTOEMISSION ELECTRON GUNS* Charles K. Sinclair # , Cornell voltage DC electron guns with photoemission cathodes are a natural choice for generating the beams gradient in these guns. The photocathode operational lifetime is limited by the gun vacuum and by ion back

  1. 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}

  2. Journal of Electron Spectroscopy and Related Phenomena 136 (2004) 1520 Temperature-dependence of Kondo resonance in CeSi2 studied by

    E-Print Network [OSTI]

    Oh, Se-Jung

    2004-01-01

    ). heavy-electron compounds [7]. In Ce-based heavy Fermion systems, the Kondo energy scale, , typically spectroscopy (RPES); Single impurity Anderson model (SIAM) 1. Introduction In the photoemission community, Ce photoemission (UPS) can reach this resolution limits currently. The most commonly used method to extract the 4f

  3. Time delay in photoemission by attosecond laser pulses

    E-Print Network [OSTI]

    J. Marciak-Kozlowska; M. Kozlowski

    2013-02-15

    Recently the time delay in the attosecond photoemission was observed (Science,2010). In this paper we propose the description of that time delay in the framework of hyperbolic heat transport equation. We argue that the observed time delay 20 as is of the order of the thermal relaxation time for hyperbolic quantum heat transport. As the generalization of the standard quantum mechanics we propose new local Schroedinger equation with c=finite

  4. 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.

  5. Normal-Incidence Photoemission Electron Microscopy (NI-PEEM) for Imaging Surface Plasmon Polaritons

    E-Print Network [OSTI]

    Aeschlimann, Martin

    Philip Kahl & Simone Wall & Christian Witt & Christian Schneider & Daniela Bayer & Alexander Fischer-incidence photoemission microscopy P. Kahl :S. Wall :C. Witt :M. Horn-von Hoegen : F.

  6. Anisotropic scattering rate in Fe-substituted Bi 2 Sr 2 Ca ( Cu 1 - x Fe x ) 2 O 8 + ?

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

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

    2015-05-01

    We measured the electronic structure of Fe-substituted Bi2212 using angle-resolved photoemission spectroscopy. 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 suppresses very strongly the coherence weight around the antinodes.

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

    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.

  8. Standing-wave excited soft x-ray photoemission microscopy: application to Co microdot magnetic arrays

    E-Print Network [OSTI]

    Gray, Alexander

    2011-01-01

    Standing-wave excited soft x-ray photoemission microscopy:excitation with soft x-ray standing-waves generated by Braggmirror substrate. Standing wave is moved vertically through

  9. Photoelectron Spectroscopy under Ambient Pressure and Temperature Conditions

    SciTech Connect (OSTI)

    Ogletree, D. Frank; Bluhm, Hendrik; Hebenstreit, Eleonore B.; Salmeron, Miquel

    2009-02-27

    We describe the development and applications of novel instrumentation for photoemission spectroscopy of solid or liquid surfaces in the presence of gases under ambient conditions or pressure and temperature. The new instrument overcomes the strong scattering of electrons in gases by the use of an aperture close to the surface followed by a differentially-pumped electrostatic lens system. In addition to the scattering problem, experiments in the presence of condensed water or other liquids require the development of special sample holders to provide localized cooling. We discuss the first two generations of Ambient Pressure PhotoEmission Spectroscopy (APPES) instruments developed at synchrotron light sources (ALS in Berkeley and BESSY in Berlin), with special focus on the Berkeley instruments. Applications to environmental science and catalytic chemical research are illustrated in two examples.

  10. Vacuum space charge effect in laser-based solid-state photoemission spectroscopy

    E-Print Network [OSTI]

    Graf, Jeff

    2010-01-01

    G. et al. Development of a vacuum ultraviolet laser-basedB¨ hlow, M. & Kipp, L. Vacuum space-charge e?ects u inVacuum space charge e?ect in laser-based solid-state

  11. 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.

  12. SPIN POLARIZED PHOTOELECTRON SPECTROSCOPY AS A PROBE OF MAGNETIC SYSTEMS.

    SciTech Connect (OSTI)

    JOHNSON, P.D.; GUNTHERODT, G.

    2006-11-01

    Spin-polarized photoelectron spectroscopy has developed into a versatile tool for the study of surface and thin film magnetism. In this chapter, we examine the methodology of the technique and its recent application to a number of different problems. We first examine the photoemission process itself followed by a detailed review of spin-polarization measurement techniques and the related experimental requirements. We review studies of spin polarized surface states, interface states and quantum well states followed by studies of the technologically important oxide systems including half-metallic transition metal oxides, ferromagnet/oxide interfaces and the antiferromagnetic cuprates that exhibit high Tc Superconductivity. We also discuss the application of high-resolution photoemission with spin resolving capabilities to the study of spin dependent self energy effects.

  13. Effect of humid air exposure on photoemissive and structural properties of KBr thin film photocathode

    E-Print Network [OSTI]

    Rai, R; Ghosh, N; Singh, B K

    2014-01-01

    We have investigated the influence of water molecule absorption on photoemissive and structural properties of potassium bromide (KBr) thin film photocathode under humid air exposure at relative humidity (RH) 65%. It is evident from photoemission measurement that the photoelectron yield of KBr photocathode is degraded exponentially with humid air exposed time. Structural studies of the "as-deposited" and "humid air aged" films reveal that there is no effect of RH on film's crystalline face centered cubic (fcc) structure. However, the average crystallite size of "humid air exposed film" KBr film has been increased as compared to "as-deposited". In addition, topographical properties of KBr film are also examined by means of scanning electron microscope (SEM), transmission electron microscope (TEM) and atomic force microscope (AFM) and it is observed that granular characteristic of film has been altered, even for short exposure to humid air.

  14. Effects of a modular two-step ozone-water and annealing process on silicon carbide graphene

    SciTech Connect (OSTI)

    Webb, Matthew J., E-mail: matthew.webb@cantab.net; Lundstedt, Anna; Grennberg, Helena [Department of Chemistry—BMC, Uppsala University, Box 576, SE-751 23 Uppsala (Sweden); Polley, Craig; Niu, Yuran; Zakharov, Alexei A.; Balasubramanian, Thiagarajan [MAX IV Laboratory, Lund University, 22100 Lund (Sweden); Dirscherl, Kai [DFM—Danish Fundamental Metrology, Matematiktorvet 307, DK-2800 Lyngby (Denmark); Burwell, Gregory; Guy, Owen J. [College of Engineering, Faraday Tower, Singleton Park, Swansea University, Swansea SA2 8PP (United Kingdom); Palmgren, Pål [VG Scienta Scientific AB, Box 15120, Vallongatan 1, SE-750 15 Uppsala (Sweden); Yakimova, Rositsa [Department of Physics, Chemistry, and Biology, Linköping University, SE-581 83 Linköping (Sweden)

    2014-08-25

    By combining ozone and water, the effect of exposing epitaxial graphene on silicon carbide to an aggressive wet-chemical process has been evaluated after high temperature annealing in ultra high vacuum. The decomposition of ozone in water produces a number of oxidizing species, however, despite long exposure times to the aqueous-ozone environment, no graphene oxide was observed after the two-step process. The systems were comprehensively characterized before and after processing using Raman spectroscopy, core level photoemission spectroscopy, and angle resolved photoemission spectroscopy together with low energy electron diffraction, low energy electron microscopy, and atomic force microscopy. In spite of the chemical potential of the aqueous-ozone reaction environment, the graphene domains were largely unaffected raising the prospect of employing such simple chemical and annealing protocols to clean or prepare epitaxial graphene surfaces.

  15. 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.

  16. 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, ?/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 ?/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. 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, ?/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 ?/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.

  18. Photo-emission rate of sQGP at finite density

    E-Print Network [OSTI]

    Kwanghyun Jo; Sang-Jin Sin

    2010-06-09

    We calculate the thermal spectral function of SYM plasma with finite density using holographic technique. We take the RN-AdS black hole as the dual gravity theory. In the presence of charge, vector modes of gravitational and electromagnetic perturbation are coupled with each other. By introducing master variables for these modes, we solve the coupled system and calculate spectral function. We also calculated photoemission rate of SYM plasma from spectral function for light like momentum, AC conductivity and their density dependence. The suppression of the conductivity in high density is noticed, which might be yet another mechanism for the Jet quenching phenomena in RHIC experiment.

  19. 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.

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

    Office of Scientific and Technical Information (OSTI)

    Overdoped La2-xSrxCuO4 Superconductors Revealed by Dilute Fe Doping: A Combined Neutron Scattering and Angle-Resolved Photoemission Study Citation Details In-Document Search...

  1. Excited electron dynamics in bulk ytterbium: Time-resolved two-photon photoemission and GW+T ab initio calculations

    E-Print Network [OSTI]

    Aeschlimann, Martin

    relaxation dynamics is played by the electronic structure of the system close to the Fermi level. For exampleExcited electron dynamics in bulk ytterbium: Time-resolved two-photon photoemission and GW+T ab November 2007 The excited electron dynamics in ytterbium is investigated by means of the time-resolved two

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

    E-Print Network [OSTI]

    Jozwiak, Chris M.

    2010-01-01

    graphene for substantially improved target lifetimes 77,78 may be an attractive option, and could be performed in the present preparation

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

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 OutreachProductswsicloudwsiclouddenDVA N C E D B LReports from the CloudGEGR-N Goods PO 1COOP FAQ

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

    Office of Scientific and Technical Information (OSTI)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefield MunicipalTechnicalInformation4563AbuseConnectJournal(Conference)Detectors

  5. Characterization of a circular optical nanoantenna by nonlinear photoemission electron microscopy

    E-Print Network [OSTI]

    Kaiser, Thomas; Qi, Jing; Klein, Angela; Steinert, Michael; Menzel, Christoph; Rockstuhl, Carsten; Pertsch, Thomas

    2015-01-01

    We report on the investigation of an advanced circular plasmonic nanoantenna under ultrafast excitation using nonlinear photoemission electron microscopy (PEEM) under near-normal incidence. The circular nanoantenna is enhanced in its performance by a supporting grating and milled out from a gold film. The considered antenna shows a sophisticated physical resonance behavior that is ideal to demonstrate the possibilities of PEEM for the experimental investigations of plasmonic effects on the nanoscale. Field profiles of the antenna resonance for both possible linear polarizations of the incident field are measured with high spatial resolution. In addition, outward propagating Hankel plasmons, which are also excited by the structure, are measured and analyzed. We compare our findings to measurements of an isolated plasmonic nanodisc resonator and scanning near-field optical microscopy (SNOM) measurements of both structures. All results are in very good agreement with numerical simulations as well as analytial mo...

  6. 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.

  7. 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.

  8. 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.

  9. Final state effects in photoemission studies of Fermi surfaces This article has been downloaded from IOPscience. Please scroll down to see the full text article.

    E-Print Network [OSTI]

    the photoemission intensity distributions measured as a function of electron detection angle and photon energy of Contents and more related content is available HOME | SEARCH | PACS & MSC | JOURNALS | ABOUT | CONTACT US of temperatures allowing for phase transitions 3 Author to whom any correspondence should be addressed. 0953

  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. Sandia Energy - Nonlinear Laser Spectroscopy

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

    Nonlinear Laser Spectroscopy Home Transportation Energy Predictive Simulation of Engines Diagnostics Gas-Phase Diagnostics Nonlinear Laser Spectroscopy Nonlinear Laser...

  12. Photoemission and optical constant measurements of Cesium Iodide thin film photocathode

    E-Print Network [OSTI]

    Triloki,; Gupta, Nikita; Jammal, Nabeel F A; Singh, B K

    2014-01-01

    Performance of cesium iodide (CsI) as a reflective photocathode is presented. Absolute quantum efficiency (QE) measurement of 500 nm thick CsI film has been carried out in the wavelength range of 150 nm to 200 nm. Optical absorbance of 500 nm thick CsI film in the spectral range of 190 nm to 900 nm is analyzed and optical energy band gap is calculated using Tauc plot. To see the dispersive behavior of CsI film, refractive index has been determined by envelop plot of transmittance data, using Swanepoel method. Additional information on morphological and elemental composition results of CsI film, gained by atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS), respectively are also reported in present work.

  13. 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.

  14. Electronic structure reconstruction across the antiferromagnetic transition in TaFe????Te? 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 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 containsmore »similar ingredients as the parent compounds of iron-based superconductors.« less

  15. 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

  16. 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.

  17. From a Single-Band Metal to a High-Temperature Superconductor via Two Thermal Phase Transitions

    SciTech Connect (OSTI)

    He, R.-H.; Hashimoto, M.; Karapetyan, H.; Koralek, J.D.; Hinton, J.P.; Testaud, J.P.; Nathan, V.; Yoshida, Y.; Yao, H.; Tanaka, K.; Meevasana, W.; Moore, R.G.; Lu, D.H.; Mo, S.-K.; Ishikado, M.; Eisaki, H.; Hussain, Z.; Devereaux, T.P.; Kivelson, S.A.; Orenstein, J.; Kapitulnik, A.

    2011-11-08

    The nature of the pseudogap phase of cuprate high-temperature superconductors is one of the most important unsolved problems in condensed matter physics. We studied the commencement of the pseudogap state at temperature T* using three different techniques (angle-resolved photoemission spectroscopy, polar Kerr effect, and time-resolved reflectivity) on the same optimally-doped Bi2201 crystals. We observe the coincident onset at T* of a particle-hole asymmetric antinodal gap, a non-zero Kerr rotation, and a change in the relaxational dynamics, consistent with a phase transition. Upon further cooling, spectroscopic signatures of superconductivity begin to grow close to the superconducting transition temperature (T{sub c}), entangled in an energy-momentum dependent fashion with the pre-existing pseudogap features.

  18. Optical gyrotropy as a test for dynamic chiral magnetic effect of Weyl semimetals

    E-Print Network [OSTI]

    Pallab Goswami; Girish Sharma; Sumanta Tewari

    2015-10-06

    Recent angle resolved photoemission spectroscopy measurements have identified an inversion symmetry breaking Weyl semimetal phase in TaAs and NbAs. In an inversion symmetry breaking Weyl semimetal the left and the right handed Weyl points can occur at different energies and the energy mismatch between the Weyl points of opposite chirality is known as the chiral chemical potential. In the presence of the chiral chemical potential, the nontrivial Berry curvature of the Weyl fermions gives rise to the \\emph{dynamic} chiral magnetic effect. This describes how a time dependent magnetic field leads to an electrical current along the applied field direction, which is also proportional to the field strength. We derive a general formula for the dynamic chiral magnetic conductivity of the inversion symmetry breaking Weyl semimetal. We show that the measurement of the natural optical activity or rotary power provides a direct confirmation of the existence of the dynamic chiral magnetic effect in inversion symmetry breaking Weyl semimetals.

  19. 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.

  20. 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 ? bands follows a BCS-like variation with temperature with ?0 ~ 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 ? 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 ? Fermi sheet and therefore we cannot exclude the possibility of interband scattering as its origin.« less

  1. High Pressure Scanning Tunneling Microscopy and High Pressure X-ray Photoemission Spectroscopy Studies of Adsorbate Structure, Composition and Mobility during Catalytic Reactions on A Model Single Crystal

    E-Print Network [OSTI]

    Montano, M.O.

    2006-01-01

    a typical day Map of synchrotron radiation source STM image3.18. Figure 3.18 – Map of a synchrotron radiation source.

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

    E-Print Network [OSTI]

    Hueso, J. L.

    2010-01-01

    XPS measurements 2.3. Catalytic oxidation tests of CO 2.4.background [27] and [28]. 2.3. Catalytic oxidation testsof CO Catalytic oxidation experiments of CO were carried out

  3. High Pressure Scanning Tunneling Microscopy and High Pressure X-ray Photoemission Spectroscopy Studies of Adsorbate Structure, Composition and Mobility during Catalytic Reactions on A Model Single Crystal

    E-Print Network [OSTI]

    Montano, M.O.

    2006-01-01

    Exchanger In STM experiments in general, and especially high-pressure andPressure STM Chamber Scan Head Sample Stage Tips Tip Exchangerlow base pressure. Once the sample or tip exchanger has been

  4. 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.

  5. ELECTRON PARAMAGNETIC RESONANCE SPECTROSCOPY

    E-Print Network [OSTI]

    Crofts, Antony R.

    . Excellent textbooks in EPR spectroscopy cover basic materials [2­5]. Many monographs are devoted to the consideration of more specific topics including theory, instrumentation, or application to selected paramagnetic species [6­19]. Handbooks of EPR spectroscopy [20, 21] are also available, as are periodic reviews

  6. 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.

  7. Toward pure electronic spectroscopy

    E-Print Network [OSTI]

    Petrovi?, Vladimir, 1978-

    2009-01-01

    In this thesis is summarized the progress toward completing our understanding of the Rydberg system of CaF and developing Pure Electronic Spectroscopy. The Rydberg system of CaF possesses a paradigmatic character due to ...

  8. Pulsed Zeeman spectroscopy 

    E-Print Network [OSTI]

    Cullen, Raymond Paul

    1967-01-01

    PULSED ZEEMAN SPECTROSCOPY A Thesis Raymond P. Cullen Submitted to the Graduate Collepe of the Texas MM University in partial fulfillment of the requirements for the degree of MASTER OE SCIENCE August 1967 Major Subject: Chemistry PULSRD... ZEEHA&'I SPRCTPOSC::)Py A The. ", is by Raymond P. Cullen Approved es to style and content by: (Chairman o~ Commi. tee) August 1967 Pulsed Zceman Spectroscopy (August 1967) Raymond P. Cullen, B. S. , Texas A6M University Directed by: Dr...

  9. 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.

  10. Spectroscopy of semiconductor materials

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach Home RoomPreservation ofAlbuquerque|SensitiveApril 2, 2014 SmithSpectroscopy ofSpectroscopy ofAg 3 VO

  11. DIFFUSING ACOUSTIC WAVE SPECTROSCOPY: FIELD FLUCTUATION SPECTROSCOPY WITH MULTIPLY

    E-Print Network [OSTI]

    Page, John

    DIFFUSING ACOUSTIC WAVE SPECTROSCOPY: FIELD FLUCTUATION SPECTROSCOPY WITH MULTIPLY SCATTERED Martyrs, B.P. 166, 38042 Grenoble Cedex 9, France Abstract. Diffusing Acoustic Wave Spectroscopy (DAWS that acoustic waves, and ultrasonic waves in particular, are playing in understanding the rich diversity of wave

  12. Supplemental Discussion Infrared spectroscopy

    E-Print Network [OSTI]

    Brown, Michael E.

    Supplemental Discussion Infrared spectroscopy We obtained near infrared reflectance spectra of 26 /~160 (see Supplemental Figure 1). The region between 1.81 and 1.89 µm has residual contamination the 50 Myr time period (see Supplemental Figure 2). doi: 10.1038/nature05619 SUPPLEMENTARY INFORMATION

  13. Laser-Induced Breakdown Spectroscopy

    E-Print Network [OSTI]

    Nizkorodov, Sergey

    LIBS-1 Laser-Induced Breakdown Spectroscopy LIBS ANALYSIS OF METAL SURFACES Last updated: June 17, 2014 #12;LIBS-2 Laser­Induced Breakdown Spectroscopy (LIBS) LIBS ANALYSIS OF METAL SURFACES of species at a distance or in hard­to­reach or hazardous environments. Laser­Induced Breakdown Spectroscopy

  14. Plasmon Enhanced Photoemission

    E-Print Network [OSTI]

    Polyakov, Aleksandr

    2013-01-01

    avoid forming a carbon contamination layer that will fill upIf, however, the contamination layer does form, it can beout into air, a contamination layer would form that resulted

  15. Plasmon Enhanced Photoemission

    E-Print Network [OSTI]

    Polyakov, Aleksandr N.

    2012-01-01

    avoid forming a carbon contamination layer that will fill upIf, however, the contamination layer does form, it can beout into air, a contamination layer would form that resulted

  16. Plasmon Enhanced Photoemission

    E-Print Network [OSTI]

    Polyakov, Aleksandr

    2013-01-01

    contamination layer does form, it can be cleaned o? with the following procedure: Recipe 11 Sample Cleaningand Cleaning Once the sample is prepared it must be kept in a nitrogen atmosphere to avoid forming a carbon contamination layer

  17. Plasmon Enhanced Photoemission

    E-Print Network [OSTI]

    Polyakov, Aleksandr N.

    2012-01-01

    contamination layer does form, it can be cleaned off with the following procedure: Recipe 11 Sample Cleaningand Cleaning Once the sample is prepared it must be kept in a nitrogen atmosphere to avoid forming a carbon contamination layer

  18. Plasmon Enhanced Photoemission

    E-Print Network [OSTI]

    Polyakov, Aleksandr

    2013-01-01

    Atomic Layer Deposition . . . . . . . . . . . . . . . . . . . . .Temperature Al2O3 Atomic Layer Deposition. Chem. Mater. 16,Assisted Atomic Layer Deposition: Basics, Opportunities, and

  19. Plasmon Enhanced Photoemission

    E-Print Network [OSTI]

    Polyakov, Aleksandr N.

    2012-01-01

    ALD Atomic Layer Deposition . . . . . . . . . . . . .Temperature Al2O3 Atomic Layer Deposition. Chem. Mater. 16,Assisted Atomic Layer Deposition: Basics, Opportunities, and

  20. 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.

  1. Direct spectroscopic evidence for completely filled Cu 3d shell in BaCu?As? and ? – BaCu?Sb?

    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 BaCu?As? and ? - BaCu?Sb?. 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 BaCu?As? 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 ? - BaCu?Sb? without the pnictide-pnictide interlayer bonding characteristic of the collapsed tetragonal phase suggests that the short interlayer distance in BaCu?As? follows from the stability of the Cu?¹ rather than the other way around. Our results confirm the prediction that BaCu?As? is an sp metal with weak electronic correlations.« less

  2. Spectroscopy of $^{26}$F

    E-Print Network [OSTI]

    Stanoiu, M; Sorlin, O; Dombradi, Zs; Azaiez, F; Brown, B A; Borcea, C; Bourgeois, C; Elekes, Z; Fülöp, Zs; Grévy, S; Guillemaud-Mueller, D; Ibrahim, F; Kerek, A; Krasznahorkay, A; Lewitowicz, M; Lukyanov, S M; Mrazek, J; Negoita, F; Penionzhkevich, Yu -E; Podolyak, Zs; Porquet, M G; Roussel-Chomaz, P; Saint-Laurent, M G; Savajols, H; Sletten, G; Timar, J; Timis, C

    2012-01-01

    The structure of the weakly-bound $^{26}_{\\;\\;9}$F$_{17}$ odd-odd nucleus, produced from $^{27,28}$Na nuclei, has been investigated at GANIL by means of the in-beam $\\gamma$-ray spectroscopy technique. A single $\\gamma$-line is observed at 657(7) keV in $^{26}_{9}$F which has been ascribed to the decay of the excited J=$2^+$ state to the J=1$^+$ ground state. The possible presence of intruder negative parity states in $^{26}$F is also discussed.

  3. Dark Matter Velocity Spectroscopy

    E-Print Network [OSTI]

    Eric G. Speckhard; Kenny C. Y. Ng; John F. Beacom; Ranjan Laha

    2015-07-31

    Dark matter decays or annihilations that produce line-like spectra may be smoking-gun signals. However, even such distinctive signatures can be mimicked by astrophysical or instrumental causes. We show that velocity spectroscopy-the measurement of energy shifts induced by relative motion of source and observer-can separate these three causes with minimal theoretical uncertainties. The principal obstacle has been energy resolution, but upcoming experiments will reach the required 0.1% level. As an example, we show that the imminent Astro-H mission can use Milky Way observations to separate possible causes of the 3.5-keV line. We discuss other applications.

  4. 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.

  5. Fourier Transform Infrared (FTIR) Spectroscopy

    E-Print Network [OSTI]

    Gerwert, Klaus

    Fourier Transform Infrared (FTIR) Spectroscopy Klaus Gerwert, Lehrstuhl fu¨r Biophysik, Ruhr, Germany Based in part on the previous version of this Encyclopedia of Life Sciences (ELS) article, Fourier Transform IR by Johannes Orphal. Fourier transform infrared (FTIR) spectroscopy is an experimental technique

  6. 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.

  7. JOURNAL DE PHYSIQUE Colloque C4, supptkment au no 5, Tome 35, Mai 1974, page C4-261 X-RAY PHOTOEMISSION SPECTRA FROM AMORPHOUS Au-Ge

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    -RAY PHOTOEMISSION SPECTRA FROM AMORPHOUS Au-Ge AND Ag-Ge ALLOYS J. FUKUSHIMA, K. TAMURA and H. END0 Department amorphes Au-Ge et Ag-Ge. La position et la forme de la raie principale, associke aux bandes-d de 1'Au dans les spectres,sont considkrablement modifikes par l'addition du Ge, tandis que celle associee aux

  8. Protected subspace Ramsey spectroscopy

    E-Print Network [OSTI]

    Laurin Ostermann; David Plankensteiner; Helmut Ritsch; Claudiu Genes

    2014-11-27

    We study a modified Ramsey spectroscopy technique employing slowly decaying states for quantum metrology applications using dense ensembles. While closely positioned atoms exhibit superradiant collective decay and dipole-dipole induced frequency shifts, recent results [Ostermann, Ritsch and Genes, Phys. Rev. Lett. \\textbf{111}, 123601 (2013)] suggest the possibility to suppress such detrimental effects and achieve an even better scaling of the frequency sensitivity with interrogation time than for noninteracting particles. Here we present an in-depth analysis of this 'protected subspace Ramsey technique' using improved analytical modeling and numerical simulations including larger 3D samples. Surprisingly we find that using sub-radiant states of $N$ particles to encode the atomic coherence yields a scaling of the optimal sensitivity better than $1/\\sqrt{N}$. Applied to ultracold atoms in 3D optical lattices we predict a precision beyond the single atom linewidth.

  9. 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 5–10 × 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.

  10. Fiber Laser Based Nonlinear Spectroscopy

    E-Print Network [OSTI]

    Adany, Peter

    2012-08-31

    To date, nonlinear spectroscopy has been considered an expensive technique and confined mostly to experimental laboratory settings. Over recent years, optical-fiber lasers that are highly reliable, simple to operate and relatively inexpensive have...

  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. 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.

  13. Diagnosing breast cancer using diffuse reflectance spectroscopy and intrinsic fluorescence spectroscopy

    E-Print Network [OSTI]

    Fitzmaurice, Maryann

    Using diffuse reflectance spectroscopy and intrinsic fluorescence spectroscopy, we have developed an algorithm that successfully classifies normal breast tissue, fibrocystic change, fibroadenoma, and infiltrating ductal ...

  14. Superconducting order parameter in nonmagnetic borocarbides RNi?B?C (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 LuNi?B?C and YNi?B?C. 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 LuNi?B?C crystals and one set ofmore »YNi?B?C 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

  15. Twofold enhancement of the hidden-order/large-moment antiferromagnetic phase boundary in the URu2-xFexSi? 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-xFexSi? reveal a twofold enhancement of the “hidden-order” (HO)/large-moment antiferromagnetic (LMAFM) phase boundary T?(x). The T?(Pch) curve, obtained by converting x to “chemical pressure” Pch, is strikingly similar to the T?(P) curve, where P is applied pressure, for URu?Si? 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 URu?Si? occurs at x ? 0.2 (Pch?1.5 GPa) in URu2-xFexSi?. URu2-xFexSi? 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

  16. A Roadmap For Meson Spectroscopy

    E-Print Network [OSTI]

    M. G. Olsson

    2002-07-31

    An efficient classification of light quark meson states is discussed based on the dominance of angular and radial quark excitation. A synthesis of Regge and quark dynamics allows a natural unification of light quark-antiquark spectroscopies and indicates the states that fall outside this category such as molecules, hybrids, and glueballs.

  17. High-spin nuclear spectroscopy

    SciTech Connect (OSTI)

    Diamond, R.M.

    1986-07-01

    High-spin spectroscopy is the study of the changes in nuclear structure, properties, and behavior with increasing angular momentum. It involves the complex interplay between collective and single-particle motion, between shape and deformation changes, particle alignments, and changes in the pairing correlations. A review of progress in theory, experimentation, and instrumentation in this field is given. (DWL)

  18. Thermal Lens Spectroscopy Mladen Franko

    E-Print Network [OSTI]

    Reid, Scott A.

    Thermal Lens Spectroscopy Mladen Franko Laboratory of Environmental Research, University of Nova-beam Instruments 5 3.3 Differential Thermal Lens Instruments 7 3.4 Multiwavelength and Tunable Thermal Lens Spectrometers 8 3.5 Circular Dichroism TLS Instruments 9 3.6 Miniaturization of Thermal Lens Instruments 9 4

  19. Ramsey spectroscopy with squeezed light

    E-Print Network [OSTI]

    Kenan Qu; G. S. Agarwal

    2013-07-12

    Traditional Ramsey spectroscopy has the frequency resolution $2\\pi/T$, where $T$ is the time separation between two light fields. Using squeezed states and two-atom excitation joint detection, we present a new scheme achieving a higher resolution $\\pi/T$. We use two mode squeezed light which exhibits strong entanglement.

  20. GUEST EDITORIAL Coherent Multidimensional Optical Spectroscopy

    E-Print Network [OSTI]

    Mukamel, Shaul

    motions offering dramatically more information. In 1D spectroscopy, the linear electrical polarization to the picosecond, electronically off-resonant, coher- ent anti-Stokes Raman spectroscopy (CARS) measurements of

  1. Electrochemistry, Photoelectrochemistry And Photoelectron Spectroscopy Of Nanostructured Metal Oxides

    E-Print Network [OSTI]

    Södergren, S

    1997-01-01

    Electrochemistry, Photoelectrochemistry And Photoelectron Spectroscopy Of Nanostructured Metal Oxides

  2. Valence-band electronic structure of CdO, ZnO, and MgO from x-ray photoemission spectroscopy and quasi-particle-corrected density-functional theory calculations

    E-Print Network [OSTI]

    Schleife, André

    form as transparent contacts in, for example, photovoltaic devices, liquid-crystal displays, and light binding energy of 60 meV,6 will likely form a central component of many II-O-based optoelectronic devices

  3. Fermion correlators in non-abelian holographic superconductors

    E-Print Network [OSTI]

    Steven S. Gubser; Fabio D. Rocha; Amos Yarom

    2010-02-24

    We consider fermion correlators in non-abelian holographic superconductors. The spectral function of the fermions exhibits several interesting features such as support in displaced Dirac cones and an asymmetric distribution of normal modes. These features are compared to similar ones observed in angle resolved photoemission experiments on high T_c superconductors. Along the way we elucidate some properties of p-wave superconductors in AdS_4 and discuss the construction of SO(4) superconductors.

  4. 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 present 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 CuO2layers, and doping dependence can be understood straightforwardly in terms of several aspects of electron-phonon coupling in layered correlated materials.

  5. Spectroscopy

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfateSciTechtail.Theory ofDidDevelopment Top ScientificTechnologies |DOE RateBusiness

  6. Spectroscopy

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach Home RoomPreservation ofAlbuquerque|SensitiveApril 2, 2014 Smith

  7. 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.

  8. Charmed baryon spectroscopy with Belle

    SciTech Connect (OSTI)

    Lesiak, Tadeusz [Institute of Nuclear Physics PAN, Radzikowskiego 152, 31-142 Cracow (Poland)

    2007-02-27

    Recent studies concerning charmed baryon spectroscopy, performed by the Belle collaboration, are briefly described. We report the first observation of two new baryons {xi}cx(2980) and {xi}cx(3077), a precise determination of the masses of {xi}c(2645) and {xi}c(2815), observation of the {lambda}c(2940)+ and experimental constraints on the possible spin-parity of the {lambda}c(2880)+. Observations of several exclusive decays of B mesons to the final states containing charmed baryons are also briefly presented.

  9. 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.

  10. Sandia Energy - Photoionization Mass Spectroscopy

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach Home RoomPreservation of Fe(II)Geothermal Energy &WaterNewPhotoionization Mass Spectroscopy Home

  11. Pairing, pseudogap and Fermi arcs in cuprates

    SciTech Connect (OSTI)

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

    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. We demonstrate that these findings resolve a number of seemingly contradictory scenarios.

  12. 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.

  13. 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–?–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 ?(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

  14. 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.

  15. 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 FS superstructuremore »withQ15(1/2,1/2,1/2) appears in all LNO films, while a tensile-strained LNO film has an additional Q2 5 (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

  16. 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 (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, 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.

  17. Pairing, pseudogap and Fermi arcs in cuprates

    SciTech Connect (OSTI)

    Kaminski, Adam [Iowa State Univ., Ames, IA (United States); Gu, Genda [Brookhaven National Lab. (BNL), Upton, NY (United States); Kondo, Takeshi [The Univ. of Tokyo, Chiba (Japan); Takeuchi, Tsunehiro [Nagoya Univ., Nagoya (Japan)

    2014-10-31

    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. We demonstrate that these findings resolve a number of seemingly contradictory scenarios.

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

    SciTech Connect (OSTI)

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

  19. 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.; Bud’ko, 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 transitions—topological changes of the Fermi surface—occur 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~0.15—between 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 Fermiologymore »in 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

  20. Latent instabilities in metallic LaNiO? 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 LaNiO? (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 withQ? = (1/2,1/2,1/2) appears in all LNO films, while a tensile-strained LNO film has an additional Q? = (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

  1. 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

  2. PHYSICAL REVIEW B 84, 075406 (2011) Nonalloying surface reconstructions of ultrathin Sn films on Cu(111) investigated with LEED, XPS,

    E-Print Network [OSTI]

    Luh, Dah-An

    2011-01-01

    (111) investigated with LEED, XPS, and photoelectron extended fine structure analysis Xihui Liang,1 investigated with low energy electron diffraction (LEED), x-ray photoemission spectroscopy (XPS), and analysis diffraction (LEED), x-ray photoemission spectroscopy (XPS), and analysis of photoemission extended fine

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

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

    On-Board Measurement of Ammonia and Nitrous Oxide Using Feedback Absorption Laser Spectroscopy Combined with Amplified Resonance and Low Pressure Sampling Cummins...

  4. ELECTRON SPECTROSCOPY STUDIES OF CLEAN OXIDE SURFACES, CHEMISORBED MOLECULES AND PHOTO-ASSISTED PROCESSES

    E-Print Network [OSTI]

    Lo, Wei Jen

    2011-01-01

    electron diffraction (LEED), Auger electron spectroscopy (electron diffraction (LEED), Auger electron spectroscopy (The elastic peak: LEED . . . Auger electron spectroscopy

  5. Nonlinear Spectroscopy of Trapped Ions

    E-Print Network [OSTI]

    Frank Schlawin; Manuel Gessner; Shaul Mukamel; Andreas Buchleitner

    2014-10-07

    Nonlinear spectroscopy employs a series of laser pulses to interrogate dynamics in large interacting many-body systems, and has become a highly successful method for experiments in chemical physics. Current quantum optical experiments approach system sizes and levels of complexity which require the development of efficient techniques to assess spectral and dynamical features with scalable experimental overhead. However, established methods from optical spectroscopy of macroscopic ensembles cannot be applied straightforwardly to few-atom systems. Based on the ideas proposed in [M. Gessner et al. New J. Phys. 16 092001 (2014)], we develop a diagrammatic approach to construct nonlinear measurement protocols for controlled quantum systems and discuss experimental implementations with trapped ion technology in detail. These methods in combination with distinct features of ultra-cold matter systems allow us to monitor and analyze excitation dynamics in both the electronic and vibrational degrees of freedom. They are independent of system size, and can therefore reliably probe systems where, e.g., quantum state tomography becomes prohibitively expensive. We propose signals that can probe steady state currents, detect the influence of anharmonicities on phonon transport, and identify signatures of chaotic dynamics near a quantum phase transition in an Ising-type spin chain.

  6. 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.

  7. 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.

  8. 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 f¹more »(Ce³?) component. The spectral weight of f¹ 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

  9. 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 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 f¹more »(Ce³?) component. The spectral weight of f¹ 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

  10. Noise autocorrelation spectroscopy with coherent Raman scattering

    E-Print Network [OSTI]

    Loss, Daniel

    LETTERS Noise autocorrelation spectroscopy with coherent Raman scattering XIAOJI G. XU, STANISLAV O to noise. Here, we present a new approach to coherent Raman spectroscopy in which high resolution is achieved by means of deliberately introduced noise. The proposed method combines the efficiency

  11. DIFFUSING ACOUSTIC WAVE TRANSPORT AND SPECTROSCOPY

    E-Print Network [OSTI]

    Page, John

    1 Chapter DIFFUSING ACOUSTIC WAVE TRANSPORT AND SPECTROSCOPY J.H. PAGE, M.L. COWAN Dept. of Physics waves, multiple scattering, energy velocity, Diffusing Acoustic Wave Spectroscopy. Abstract the diffusive transport of ultrasonic waves, and then describe a new ultrasonic technique, Diffusing Acoustic

  12. Gas-Phase Spectroscopy of Biomolecular

    E-Print Network [OSTI]

    de Vries, Mattanjah S.

    Gas-Phase Spectroscopy of Biomolecular Building Blocks Mattanjah S. de Vries1 and Pavel Hobza2 1, REMPI, computational chemistry, spectral hole burning, jet cooling Abstract Gas-phase spectroscopy lends. In recent years, we have seen enormous progress in the study of biomolecular building blocks in the gas

  13. APPLIED SPECTROSCOPY 135A focal point

    E-Print Network [OSTI]

    Denver, University of

    measured as a ratio to the mea- sured emission of CO2 and calibrated by means of a certified cylinder 2190 E. ILIFF AVE. DENVER, COLORADO 80208 Spectroscopy Applied to On-Road Mobile Source Emissions INTRODUCTION N ot to be confused with emis- sion spectroscopy, the detec- tion of mobile source emis- sions

  14. Diffractive optical elements for spectroscopy Hallvard Angelskar

    E-Print Network [OSTI]

    Johansen, Tom Henning

    Diffractive optical elements for spectroscopy by Hallvard Angelsk°ar Submitted in partial;Abstract Diffractive optical elements can be used in spectroscopy instruments to fulfill several tasks to precisely fabricate complex diffractive optical elements with feature sizes below the micrometer scale

  15. RAMAN SPECTROSCOPY OF GRAPHENE AND RELATED MATERIALS

    E-Print Network [OSTI]

    Chen, Yong P.

    structure of graphene. (b) Graphene is a zero-gap semiconductor. Its 2-D nature leads to a linear dispersionChapter 19 RAMAN SPECTROSCOPY OF GRAPHENE AND RELATED MATERIALS Isaac Childres*a,b , Luis A This chapter is a review of the application of Raman spectroscopy in characterizing the properties of graphene

  16. Evolution, biodiversity, taxonomy FTIR spectroscopy and taxonomic purpose

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Evolution, biodiversity, taxonomy FTIR spectroscopy and taxonomic purpose: Contribution. taxonomy / FTIR spectroscopy / Streptococcus / Lactobacillus Résumé -- Apport de la spectroscopie infrarouge à transformée de Fourier en taxonomie : contribution à la classification de bactéries lactiques

  17. 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...

  18. 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...

  19. THRESHOLD RADIOACTIVITY FOR BULK FOOD SAMPLES BY GAMMA SPECTROSCOPY...

    Office of Scientific and Technical Information (OSTI)

    THRESHOLD RADIOACTIVITY FOR BULK FOOD SAMPLES BY GAMMA SPECTROSCOPY Citation Details In-Document Search Title: THRESHOLD RADIOACTIVITY FOR BULK FOOD SAMPLES BY GAMMA SPECTROSCOPY...

  20. Spin-resolved two-photon photoemission study of the surface resonance state on Co/Cu,,001... O. Andreyev,1 Yu. M. Koroteev,2,3 M. Snchez Albaneda,1 M. Cinchetti,1 G. Bihlmayer,4 E. V. Chulkov,2,5 J. Lange,1

    E-Print Network [OSTI]

    Bauer, Michael

    photoemission spectra from clean Co films are found to be dominated by a peak located at a binding energy-doping of a Co 001 surface shifts an image potential state in resonance with the sp-states of the conduction band and magnetization dynamics by probing the state of crystal-induced or image-potential sur- face states.3­6 In a two

  1. April 22, 2011 Institute for Quantum Matter

    E-Print Network [OSTI]

    von der Heydt, Rüdiger

    Spectroscopy · Neutron (SNS, NIST) · THz photon (JHU) · Micro waves (JHU) · Raman (JHU) · Angle Resolved Photo #12;Spectroscopy at National facilities Spallation Neutron Source, ORNL Advanced Light Source, LBNL NIST Center for Neutron Research #12;Accomplishments 2008-present · The Experimental Frontier ­ Cold

  2. Noninvasive glucose sensing by transcutaneous Raman spectroscopy

    E-Print Network [OSTI]

    Shih, Wei-Chuan

    We present the development of a transcutaneous Raman spectroscopy system and analysis algorithm for noninvasive glucose sensing. The instrument and algorithm were tested in a preclinical study in which a dog model was used. ...

  3. Scanning tunneling spectroscopy of unoccupied surface resonances

    E-Print Network [OSTI]

    Persson, Mats

    - induced series, produced when an electron is trapped in a potential well define* *d by the image Scanning tunneling spectroscopy of unoccupied surface resonances at free-electron-like metal surfaces. T. Fond'eny, S

  4. Developments and advances in nonlinear terahertz spectroscopy

    E-Print Network [OSTI]

    Brandt, Nathaniel Curran

    2014-01-01

    Nonlinear terahertz (THz) spectroscopy is a rapidly developing field, which is concerned with driving and observing nonlinear material responses in the THz range of the electromagnetic spectrum. In this thesis, I present ...

  5. Gas-Phase IR Spectroscopy of Nucleobases

    E-Print Network [OSTI]

    de Vries, MS

    2015-01-01

    ionization spectroscopy of gas phase guanine: Evidence for2007) Imino tautomers of gas-phase guanine from mid-infraredAlkali Metal Cation Size on Gas Phase Conformation. J. Am.

  6. Anion Photoelectron Spectroscopy of Exotic Species

    E-Print Network [OSTI]

    Yen, Terry A.

    2010-01-01

    Hatami, F. , et al. , InP quantum dots embedded in GaP:spectroscopy of InP quantum dots. Journal of Physicalfor InP with applications to large quantum dots. Physical

  7. A Narrowband Ultrasonic Spectroscopy Technique for the Inspection of

    E-Print Network [OSTI]

    This thesis introduces a narrowband ultrasonic spectroscopy (NBUS) technique for non-destructive testing. NBUS

  8. The singlettriplet spectroscopy of 1,3-butadiene using cavity ring-down spectroscopy

    E-Print Network [OSTI]

    Zwier, Timothy S.

    The singlet­triplet spectroscopy of 1,3-butadiene using cavity ring-down spectroscopy Allison G of gas-phase 1,3-butadiene (C4H6) has been investigated over the region from 20 500 to 23 000 cm 1 using polyene, the electronic struc- ture of the ground and excited electronic states of 1,3- butadiene has

  9. Raman subrecoil spectroscopy of cold cesium atoms

    E-Print Network [OSTI]

    J. Ringot; P. Szriftgiser; J. C. Garreau

    2001-07-28

    We describe and characterize a setup for subrecoil stimulated Raman spectroscopy of cold cesium atoms. We study in particular the performances of a method designed to active control and stabilization of the magnetic fields across a cold-atom cloud inside a small vacuum cell. The performance of the setup is monitored by {\\em copropagative-beam} stimulated Raman spectroscopy of a cold cesium sample. The root mean-square value of the residual magnetic field is 300 $\\mu G$, with a compensation bandwidth of 500 Hz. The shape of the observed spectra is theoretically interpreted and compares very well to numerically generated spectra.

  10. 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.

  11. Spectroscopy of Supercapacitor Electrodes In Operando

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach Home RoomPreservation ofAlbuquerque|SensitiveApril 2, 2014 SmithSpectroscopy ofSpectroscopy of

  12. 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.

  13. Inelastic Tunneling Spectroscopy in Unconventional Superconductors

    E-Print Network [OSTI]

    Inelastic Tunneling Spectroscopy in Unconventional Superconductors Molecular Vibration and Single Superconductors ­ p.1/13 #12;Old Results R.C. Jaklevic and J. Lambe, Phys. Rev. Lett. 17, 1139-1140 (1966 in Unconventional Superconductors ­ p.2/13 #12;STM observation of local inelastic mode B.C. Stipe, M.A Rezaei, and W

  14. 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.

  15. 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.

  16. 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.

  17. Submitted to Applied Spectroscopy December 2006

    E-Print Network [OSTI]

    of the components. However, the blends exhibited greatly reduced PMMA backbone vibrational intensities, suggesting biomedical applications such as bone fillers or bone grafts. Of the two blend components, one is transientSubmitted to Applied Spectroscopy December 2006 Raman Characterization in Blends of Poly

  18. Optical spectroscopy of bilayer Baisong Geng

    E-Print Network [OSTI]

    Zettl, Alex

    -gate bilayer graphene device, we were able to control the carrier doping and a semiconductor bandgap the inversion symmetry between the top and bottom graphene layers. This semiconductor bandgap canOptical spectroscopy of bilayer graphene Baisong Geng 1,2 , Jason Horng 1 , Yuanbo Zhang 1

  19. Oil Classification with Fluorescence Spectroscopy Engineering Physics

    E-Print Network [OSTI]

    Oldenburg, Carl von Ossietzky Universität

    detected by these channels. The investigation used three methods to examine crude oil, heavy oil, sludge1 Oil Classification with Fluorescence Spectroscopy Engineering Physics Master of Engineering and classification of oil spills on water surfaces. It is an overview of the laser remote sensor technique

  20. Extensions of quartz-enhanced photoacoustic spectroscopy

    E-Print Network [OSTI]

    Masurkar, Amrita V

    2009-01-01

    The goal of this thesis was to perform quartz-enhanced photoacoustic spectroscopy (QEPAS) on trace concentrations of NH3 in the 1.53 pm region with a DFB laser without the use of a resonating cavity. I analyzed the process ...

  1. Defect analysis using resonant ultrasound spectroscopy 

    E-Print Network [OSTI]

    Flynn, Kevin Joseph

    2009-05-15

    ....................................................................... 6 1.3 Resonant NDT Methods....................................................................... 7 1.3.1 Impact Excitation Technique ...................................................... 7 1.3.2 Resonant Ultrasound Spectroscopy... Page Figure 3.5 First torsional mode about X axis (X Torsion 1) for samples without (left) and with (right) the notch...................................... 44 Figure 3.6 First bending mode about Y axis (Y Bend 1) for samples without (left...

  2. Theoretical and experimental investigation of polarization spectroscopy 

    E-Print Network [OSTI]

    Hanna, Sherif Fayez

    2001-01-01

    , Sweden. Polarization spectroscopy saturation curves in the co-propagating beam geometry from the excitation of OH A ²[]?-X²[] (0,0) at the Q?(8) line for sub-atmospheric pressures have been fitted to the proposed model. The model proposed in this work...

  3. 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...

  4. Raman spectroscopy of complex defined media: biopharmaceutical applications

    E-Print Network [OSTI]

    Ram, Rajeev J.

    , grown in shake flasks in batch fermentation mode, using Raman spectroscopy and explicit model glutamine, glutamate, glucose, la

  5. Two Phase Transitions Make a High-Temperature Superconductor

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

    photoemission spectroscopy (ARPES) at Beamline 5-4 of the Stanford Synchrotron Radiation Lightsource (SSRL) and Beamline 10.0.1 of the ALS, (2) high-resolution...

  6. Imaging Fourier transform spectroscopy with multi-aperture telescopes

    E-Print Network [OSTI]

    Fienup, James R.

    Imaging Fourier transform spectroscopy with multi-aperture telescopes Samuel T. Thurman and James R Hanover St., Palo Alto, CA 94304 Abstract: Fourier spectroscopy can be performed with multi Society of America OCIS codes: (300.6300) Spectroscopy, Fourier transforms; (110.6770) Telescopes; (120

  7. Fourier Transform Heterodyne Spectroscopy of Liquid Interfaces A thesis presented

    E-Print Network [OSTI]

    Mazur, Eric

    Fourier Transform Heterodyne Spectroscopy of Liquid Interfaces A thesis presented by Doo Soo Chung Abstract This thesis describes the application of a novel Fourier transform heterodyne spectroscopy of fluid interfaces 3 1.4 Organization of this thesis 5 2 Fourier Transform Heterodyne Spectroscopy 7 2

  8. Introduction and Motivation Experimental Methods in Meson Spectroscopy

    E-Print Network [OSTI]

    Credé, Volker

    Introduction and Motivation Experimental Methods in Meson Spectroscopy Glueballs and Light Mesons, Italy 03/15/2010 V. Credé Glueballs and Light-Meson Spectroscopy #12;Introduction and Motivation Summary and Outlook Outline 1 Introduction and Motivation The Quark Model of Hadrons Meson Spectroscopy 2

  9. Transition state spectroscopy of the I + HI reaction in clusters: Photoelectron spectroscopy of (n = 115)IHI-- Ar

    E-Print Network [OSTI]

    Neumark, Daniel M.

    Transition state spectroscopy of the I + HI reaction in clusters: Photoelectron spectroscopy of (n spectroscopy and dynamics of the I ] HI reaction by measuring the anion photoelectron (PE) spectra Ar, and BrHI~ É Ar were studied in our laboratory. In this paper weIHI~ É N 2 O,18,19 examine

  10. Chiral specific electron vortex beam spectroscopy

    E-Print Network [OSTI]

    J. Yuan; S. M. Lloyd; M. Babiker

    2013-07-29

    Electron vortex beams carry well-defined orbital angular momentum (OAM) about the propagation axis. Such beams are thus characterised by chirality features which make them potentially useful as probes of magnetic and other chiral materials. An analysis of the inelastic processes in which electron vortex beams interact with atoms and which involve OAM exchange is outlined, leading to the multipolar selection rules governing this chiral specific electron vortex beam spectroscopy. Our results show clearly that the selection rules are dependent on the dynamical state and location of the atoms involved. In the most favorable scenario, this form of electron spectroscopy can induce magnetic sublevel transitions which are commonly probed using circularly polarized photon beams.

  11. 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).

  12. (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.

  13. Infrared microcalorimetric spectroscopy using quantum cascade lasers

    SciTech Connect (OSTI)

    Morales Rodriguez, Marissa E [ORNL; Senesac, Larry R [ORNL; Rajic, Slobodan [ORNL; Lavrik, Nickolay V [ORNL; Smith, Barton [ORNL; Datskos, Panos G [ORNL

    2013-01-01

    We have investigated an infrared (IR) microcalorimetric spectroscopy technique that can be used to detect the presence of trace amounts of target molecules. The chemical detection is accomplished by obtaining the IR photothermal spectra of molecules absorbed on the surface of uncooled thermal micromechanical detectors. IR microcalorimetric spectroscopy requires no chemical specific coatings and the chemical specificity of the presented method is a consequence of the wavelength-specific absorption of IR photons from tunable quantum cascade lasers due to vibrational spectral bands of the analyte. We have obtained IR photothermal spectra for trace concentrations of RDX and a monolayer of 2-mercaptoethanol, over the wavelength region from 6 to 10 m. We found that in this wavelength region both chemicals exhibit a number of photothermal absorption features that are in good agreement with their respective IR spectra.

  14. 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.

  15. Spin noise spectroscopy of ZnO

    SciTech Connect (OSTI)

    Horn, H.; Berski, F.; Hübner, 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.

  16. Electronic structure of the Si(111):GaSe van der Waals-like surface termination

    E-Print Network [OSTI]

    Olmstead, Marjorie

    Electronic structure of the Si(111):GaSe van der Waals-like surface termination Reiner Rudolph-like surface termination has been determined by angle-resolved photoelectron spectroscopy using photons. This explains both the absence of a surface core-level shift in Si 2p photoelectron spectra of the terminated

  17. 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.; Oak Ridge National Lab.; Chen, X.; Lin, Qisen; Hashimoto, M.; Lu, D. H.; et al

    2015-02-23

    We report on an angle resolved photoemission (ARPES) study of bulk electron-doped perovskite iridate, (Sr1-xLax)?Ir?O?. 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 Sr?IrO?. Our observed spectral variation is consistent with the coexistence of an electronic supermodulation with structural distortion in the system.

  18. Effect of Oxygen Adsorption on the Local Properties of Epitaxial Graphene on SiC (0001)

    E-Print Network [OSTI]

    Mathieu, C; Mentes, T O; Pallecchi, E; Locatelli, A; Latil, S; Belkhou, R; Ouerghi, A

    2015-01-01

    The effect of oxygen adsorption on the local structure and electronic properties of monolayer graphene grown on SiC(0001) has been studied by means of Low Energy Electron Microscopy (LEEM), microprobe Low Energy Electron Diffraction (\\muLEED) and microprobe Angle Resolved Photoemission (\\muARPES). We show that the buffer layer of epitaxial graphene on SiC(0001) is partially decoupled after oxidation. The monitoring of the oxidation process demonstrates that the oxygen saturates the Si dangling bonds, breaks some Si-C bonds at the interface and intercalates the graphene layer. Accurate control over the oxidation parameters enables us to tune the charge density modulation in the layer.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. Ultrafast Spectroscopy of Warm Dense Matter

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach Home RoomPreservationBio-Inspired SolarAbout /Two0 - 19 Publications 1.Design » Design forSpectroscopy

  4. Spectroscopy of Supercapacitor Electrodes In Operando

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power AdministrationRobust,Field-effect Photovoltaics -7541C.3 Special Report:Spectroscopic ion beamSpectroscopy of

  5. Spectroscopy of Supercapacitor Electrodes In Operando

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power AdministrationRobust,Field-effect Photovoltaics -7541C.3 Special Report:Spectroscopic ion beamSpectroscopy

  6. Spectroscopy of Supercapacitor Electrodes In Operando

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power AdministrationRobust,Field-effect Photovoltaics -7541C.3 Special Report:Spectroscopic ionSpectroscopy of

  7. Ultrafast Spectroscopy of Warm Dense Matter

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power AdministrationRobust,Field-effectWorking With WIPPfinal design andBiofuelsUltrafastUltrafast Spectroscopy of

  8. Ultrafast Spectroscopy of Warm Dense Matter

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power AdministrationRobust,Field-effectWorking With WIPPfinal design andBiofuelsUltrafastUltrafast Spectroscopy

  9. Spectroscopy of Supercapacitor Electrodes In Operando

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach Home RoomPreservation ofAlbuquerque|SensitiveApril 2, 2014 SmithSpectroscopy of Supercapacitor

  10. Spectroscopy of Supercapacitor Electrodes In Operando

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach Home RoomPreservation ofAlbuquerque|SensitiveApril 2, 2014 SmithSpectroscopy of

  11. Symmetry-Breaking Orbital Anisotropy Observed for Detwinned Ba(Fe1-xCox)2As2 above the Spin Density Wave Transition

    SciTech Connect (OSTI)

    Yi, Ming

    2011-08-19

    Nematicity, defined as broken rotational symmetry, has recently been observed in competing phases proximate to the superconducting phase in the cuprate high temperature superconductors. Similarly, the new iron-based high temperature superconductors exhibit a tetragonal to orthorhombic structural transition (i.e. a broken C{sub 4} symmetry) that either precedes or is coincident with a collinear spin density wave (SDW) transition in undoped parent compounds, and superconductivity arises when both transitions are suppressed via doping. Evidence for strong in-plane anisotropy in the SDW state in this family of compounds has been reported by neutron scattering, scanning tunneling microscopy, and transport measurements. Here we present an angle resolved photoemission spectroscopy study of detwinned single crystals of a representative family of electron-doped iron-arsenide superconductors, Ba(Fe{sub 1-x}Co{sub x}){sub 2}As{sub 2} in the underdoped region. The crystals were detwinned via application of in-plane uniaxial stress, enabling measurements of single domain electronic structure in the orthorhombic state. At low temperatures, our results clearly demonstrate an in-plane electronic anisotropy characterized by a large energy splitting of two orthogonal bands with dominant d{sub xz} and d{sub yz} character, which is consistent with anisotropy observed by other probes. For compositions x > 0, for which the structural transition (T{sub S}) precedes the magnetic transition (T{sub SDW}), an anisotropic splitting is observed to develop above T{sub SDW}, indicating that it is specifically associated with T{sub S}. For unstressed crystals, the band splitting is observed close to T{sub S}, whereas for stressed crystals the splitting is observed to considerably higher temperatures, revealing the presence of a surprisingly large in-plane nematic susceptibility in the electronic structure.

  12. Crystallographic, electronic, thermal, and magnetic properties of single-crystal SrCo2As2

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

    Pandey, Abhishek [Ames Lab. and Iowa State Univ., Ames, IA (United States). Dept. of Physics and Astronomy; Quirinale, D. G. [Ames Lab. and Iowa State Univ., Ames, IA (United States). Dept. of Physics and Astronomy; Jayasekara, W. [Ames Lab. and Iowa State Univ., Ames, IA (United States). Dept. of Physics and Astronomy; Sapkota, A. [Ames Lab. and Iowa State Univ., Ames, IA (United States). Dept. of Physics and Astronomy; Kim, M. G. [Ames Lab. and Iowa State Univ., Ames, IA (United States). Dept. of Physics and Astronomy; Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Dhaka, R. S. [Ames Lab. and Iowa State Univ., Ames, IA (United States). Dept. of Physics and Astronomy; Lee, Y. [Ames Lab. and Iowa State Univ., Ames, IA (United States). Dept. of Physics and Astronomy; Heitmann, T. W. [Univ. of Missouri, Columbia, MO (United States). Missouri Research Reactor; Stephens, P. W. [State Univ. of New York (SUNY), Plattsburgh, NY (United States); Ogloblichev, V. [Russian Academy of Sciences, Urals Div., Ekaterinburg (Russian Federation). Inst. of Metal Physics; Kreyssig, A. [Ames Lab. and Iowa State Univ., Ames, IA (United States). Dept. of Physics and Astronomy; McQueeney, R. J. [Ames Lab. and Iowa State Univ., Ames, IA (United States). Dept. of Physics and Astronomy; Goldman, A. I. [Ames Lab. and Iowa State Univ., Ames, IA (United States). Dept. of Physics and Astronomy; Kaminski, Adam [Ames Lab. and Iowa State Univ., Ames, IA (United States). Dept. of Physics and Astronomy; Harmon, B. N. [Ames Lab. and Iowa State Univ., Ames, IA (United States). Dept. of Physics and Astronomy; Furukawa, Y. [Ames Lab. and Iowa State Univ., Ames, IA (United States). Dept. of Physics and Astronomy; Johnston, D. C. [Ames Lab. and Iowa State Univ., Ames, IA (United States). Dept. of Physics and Astronomy

    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.

  13. Two-photon spectroscopy of excitons with entangled photons

    E-Print Network [OSTI]

    Schlawin, F; Schlawin, F; Mukamel, S

    2013-01-01

    probe experiment with entangled photons. The two beams arethe light state changes from twin photons to squeezed light.139, 244110 (2013) Two-photon spectroscopy of excitons with

  14. 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...

  15. 10 Questions for a Spectroscopy Expert: Nancy Hess | Department...

    Broader source: Energy.gov (indexed) [DOE]

    share how she's using molecular level spectroscopy to protect water supplies and advance carbon capture and sequestration technologies, and how the Apollo missions, Jacques...

  16. Diffusing acoustic wave spectroscopy M. L. Cowan,1

    E-Print Network [OSTI]

    Page, John

    Diffusing acoustic wave spectroscopy M. L. Cowan,1 I. P. Jones,1, * J. H. Page,1,2, and D. A. Weitz called diffusing acoustic wave spec- troscopy DAWS . In this technique, the motion of the scatterers e the particle velocity correlation function. Potential appli- cations of diffusing acoustic wave spectroscopy

  17. Laser Locking with Doppler-free Saturated Absorption Spectroscopy

    E-Print Network [OSTI]

    Novikova, Irina

    - 1 - Laser Locking with Doppler-free Saturated Absorption Spectroscopy Paul L. Stubbs, Advisor the frequency of a 795 nm diode laser using a saturated absorption spectroscopy method. Laser locking in AMO physics is done to stabilize the frequency of lasers used in the laboratory in order to make results more

  18. Optical Spectroscopy of Hydrogenic Atoms MIT Department of Physics

    E-Print Network [OSTI]

    Seager, Sara

    Optical Spectroscopy of Hydrogenic Atoms MIT Department of Physics (Dated: September 1, 2013) This experiment is an exercise in optical spectroscopy in a study of the spectra of "hydrogenic" atoms, i.e. atoms with one "optical" electron outside a closed shell of other electrons. Measurements include finding

  19. THZ TRANSMISSION SPECTROSCOPY APPLIED TO DIELECTRICS AND MICROWAVE CERAMICS

    E-Print Network [OSTI]

    KuÂ?el, Petr

    THZ TRANSMISSION SPECTROSCOPY APPLIED TO DIELECTRICS AND MICROWAVE CERAMICS ALEXEJ PASHKIN, ELENA of Ba(Mg1/3Ta2/3)O3 (BMT) high-permittivity microwave ceramics was measured in the sub; time-resolved spectroscopy; microwave ceramics INTRODUCTION The method of time-domain terahertz

  20. EUV spectroscopy on the SSPX spheromak

    SciTech Connect (OSTI)

    Clementson, J T; Beiersdorfer, P; Gu, M F; McLean, H S; Wood, R D

    2008-03-17

    EUV plasma spectroscopy is one the diagnostics implemented at the Sustained Spheromak Physics Experiment (SSPX) at the Lawrence Livermore National Laboratory. A grating spectrometer covering the spectral region of 25-450 {angstrom} with a resolution of 0.4 {angstrom} was used as an impurity diagnostic to monitor the plasmas and to carry out atomic physics research. Several low-Z impurities have been found in the spheromak, notably B, C, N, and O. Of the heavier elements, Ti, Cu, and W were found in the plasmas. As a relatively dense and low-temperature laboratory plasma device, SSPX served as an excellent radiation source for investigation of atomic spectra in a regime not readily attained in other devices. We have injected atomic titanium and tungsten hexacarbonyl into the spheromak under different operating conditions. We also report on electron temperature and electron density measurements based on the K{alpha} lines from B IV at 60 {angstrom}.

  1. TOF spectroscopy measurement using waveform digitizer

    E-Print Network [OSTI]

    Longxiang Liu; Hongwei Wang; Yugang Ma; Xiguang Cao; Xiangzhou Cai; Jingen Chen; Guilin Zhang; Jianlong Han; Guogiang Zhang; Jifeng Hu; Xiaohe Wang

    2015-09-17

    The photoneutron source (PNS, phase 1), an electron linear accelerator (linac)-based pulsed neutron facility that uses the time-of-flight (TOF) technique, was constructed for the acquisition of nuclear data from the thorium molten salt reactor(TMSR) at the Shanghai Institute of Applied Physics (SINAP). The neutron detector signal, with the information on the pulse arrival time, pulse shape, and pulse height, was recorded by using a waveform digitizer (WFD). By using the pulse height and pulse-shape discrimination (PSD) analysis to identify neutrons and $\\gamma$-rays, the neutron TOF spectrum was obtained by employing a simple electronic design, and a new WFD-based DAQ system was developed and tested in this commissioning experiment. The developed DAQ system is characterized by a very high efficiency with respect to millisecond neutron TOF spectroscopy

  2. Review of Flicker Noise Spectroscopy in Electrochemistry

    E-Print Network [OSTI]

    Timashev, Serge F; 10.1142/S0219477507003829

    2008-01-01

    This review presents the fundamentals of Flicker-Noise Spectroscopy (FNS), a general phenomenological methodology in which the dynamics and structure of complex systems, characterized by nonlinear interactions, dissipation, and inertia, are analyzed by extracting information from various signals with stochastically varying components generated by the systems. The basic idea of FNS is to treat the correlation links present in sequences of different irregularities, such as spikes, "jumps", and discontinuities in derivatives of different orders, on all levels of the spatiotemporal hierarchy of the system under study as main information carriers. The tools to extract and analyze the information are power spectra and difference moments (structural functions) of various orders. Presently, FNS can be applied to three types of problems: (1) determination of parameters or patterns that characterize the dynamics or structural features of complex systems; (2) finding precursors of abrupt changes in the state of various ...

  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. 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.

  5. Development of the charge exchange recombination spectroscopy and the beam emission spectroscopy on the EAST tokamak

    SciTech Connect (OSTI)

    Li, Y. Y.; Fu, J.; Lyu, B., E-mail: blu@ipp.ac.cn [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, Anhui 230031 (China); Du, X. W.; Li, C. Y.; Yu, Y.; Wang, Q. P. [School of Nuclear Science and Technology, University of Science and Technology of China, Hefei, Anhui 230026 (China); Zhang, Y.; Yin, X. H.; Ye, M. Y.; Wan, B. N. [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, Anhui 230031 (China); School of Nuclear Science and Technology, University of Science and Technology of China, Hefei, Anhui 230026 (China); Hellermann, M. von [FOM-Institute for Plasma Physics “Rijnhuizen,” Association EURATOM, Trilateral Euregio Cluster, 3430BE Nieuwegein (Netherlands); Shi, Y. J. [School of Nuclear Science and Technology, University of Science and Technology of China, Hefei, Anhui 230026 (China); WCI for Fusion Theory, National Fusion Research Institute, 52 Eoeun-Dong, Yusung-Gu, Daejeon 305-333 (Korea, Republic of)

    2014-11-15

    Charge eXchange Recombination Spectroscopy (CXRS) and Beam Emission Spectroscopy (BES) diagnostics based on a heating neutral beam have recently been installed on EAST to provide local measurements of ion temperature, velocity, and density. The system design features common light collection optics for CXRS and BES, background channels for the toroidal views, multi-chord viewing sightlines, and high throughput lens-based spectrometers with good signal to noise ratio for high time resolution measurements. Additionally, two spectrometers each has a tunable grating to observe any wavelength of interest are used for the CXRS and one utilizes a fixed-wavelength grating to achieve higher diffraction efficiency for the BES system. A real-time wavelength correction is implemented to achieve a high-accuracy wavelength calibration. Alignment and calibration are performed. Initial performance test results are presented.

  6. Spectroscopy of Photovoltaic Materials: Charge-Transfer Complexes and Titanium Dioxide

    E-Print Network [OSTI]

    Dillon, Robert

    2013-01-01

    RIVERSIDE Spectroscopy of Photovoltaic Materials: Charge-DISSERTATION Spectroscopy of Photovoltaic Materials: Charge-function of photovoltaic (PV) and photocatalytic (PC)

  7. Bimolecular reaction dynamics from photoelectron spectroscopy of negative ions

    SciTech Connect (OSTI)

    Bradforth, S.E.

    1992-11-01

    The transition state region of a neutral bimolecular reaction may be experimentally investigated by photoelectron spectroscopy of an appropriate negative ion. The photoelectron spectrum provides information on the spectroscopy and dynamics of the short lived transition state and may be used to develop model potential energy surfaces that are semi-quantitative in this important region. The principles of bound [yields] bound negative ion photoelectron spectroscopy are illustrated by way of an example: a full analysis of the photoelectron bands of CN[sup [minus

  8. 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. [Department of Materials Science and Engineering, University of Texas at Dallas, Richardson, Texas 75080 (United States)] [Department of Materials Science and Engineering, University of Texas at Dallas, Richardson, Texas 75080 (United States); Galatage, R. V. [Department of Electrical Engineering, University of Texas at Dallas, Richardson, Texas 75080 (United States)] [Department of Electrical Engineering, University of Texas at Dallas, Richardson, Texas 75080 (United States); Zhernokletov, D. [Department of Physics, University of Texas at Dallas, Richardson, Texas 75080 (United States)] [Department of Physics, University of Texas at Dallas, Richardson, Texas 75080 (United States); Wallace, R. M. [Department of Materials Science and Engineering, University of Texas at Dallas, Richardson, Texas 75080 (United States) [Department of Materials Science and Engineering, University of Texas at Dallas, Richardson, Texas 75080 (United States); Department of Physics, University of Texas at Dallas, Richardson, Texas 75080 (United States)

    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.

  9. Collinear laser spectroscopy of atomic cadmium

    E-Print Network [OSTI]

    Nadja Frömmgen; Dimiter L. Balabanski; Mark L. Bissell; Jacek Biero?; Klaus Blaum; Bradley Cheal; Kieran Flanagan; Stephan Fritzsche; Christopher Geppert; Michael Hammen; Magdalena Kowalska; Kim Kreim; Andreas Krieger; Rainer Neugart; Gerda Neyens; Mustafa M. Rajabali; Wilfried Nörtershäuser; Jasna Papuga; Deyan T. Yordanov

    2015-07-14

    Hyperfine structure $A$ and $B$ factors of the atomic $5s\\,5p\\,\\; ^3\\rm{P}_2 \\rightarrow 5s\\,6s\\,\\; ^3\\rm{S}_1$ transition are determined from collinear laser spectroscopy data of $^{107-123}$Cd and $^{111m-123m}$Cd. Nuclear magnetic moments and electric quadrupole moments are extracted using reference dipole moments and calculated electric field gradients, respectively. The hyperfine structure anomaly for isotopes with $s_{1/2}$ and $d_{5/2}$ nuclear ground states and isomeric $h_{11/2}$ states is evaluated and a linear relationship is observed for all nuclear states except $s_{1/2}$. This corresponds to the Moskowitz-Lombardi rule that was established in the mercury region of the nuclear chart but in the case of cadmium the slope is distinctively smaller than for mercury. In total four atomic and ionic levels were analyzed and all of them exhibit a similar behaviour. The electric field gradient for the atomic $5s\\,5p\\,\\; ^3\\mathrm{P}_2$ level is derived from multi-configuration Dirac-Hartree-Fock calculations in order to evaluate the spectroscopic nuclear quadrupole moments. The results are consistent with those obtained in an ionic transition and based on a similar calculation.

  10. Squeezed-light spin noise spectroscopy

    E-Print Network [OSTI]

    Lucivero, Vito Giovanni; Kong, Jia; Mitchell, Morgan W

    2015-01-01

    We report quantum enhancement of Faraday rotation spin noise spectroscopy by polarization squeezing of the probe beam. Using natural abundance Rb in \\SI{100}{Torr}of N$_2$ buffer gas, and squeezed light from a sub-threshold optical parametric oscillator stabilized \\SI{20}{GHz}to the blue of the D$_1$ resonance, we observe that an input squeezing of \\SI{3.0}{dB} improves the signal-to-noise ratio by \\SI{1.5}{dB} to \\SI{2.6}{dB} over the combined (power)$\\otimes$(number density) ranges (\\SI{0.5}{mW} to \\SI{4.0}{mW})$\\otimes$(\\SI{1.5d12}{cm\\tothe{-3}} to \\SI{1.3d13}{cm\\tothe{-3}}), covering the full practical range and into the strongly-perturbed regime. We show that in these conditions squeezing improves the trade-off between statistical noise and systematic shifts, a new kind of quantum advantage.

  11. Squeezed-light spin noise spectroscopy

    E-Print Network [OSTI]

    Vito Giovanni Lucivero; Ricardo Jiménez-Martínez; Jia Kong; Morgan W. Mitchell

    2015-09-18

    We report quantum enhancement of Faraday rotation spin noise spectroscopy by polarization squeezing of the probe beam. Using natural abundance Rb in \\SI{100}{Torr}of N$_2$ buffer gas, and squeezed light from a sub-threshold optical parametric oscillator stabilized \\SI{20}{GHz}to the blue of the D$_1$ resonance, we observe that an input squeezing of \\SI{3.0}{dB} improves the signal-to-noise ratio by \\SI{1.5}{dB} to \\SI{2.6}{dB} over the combined (power)$\\otimes$(number density) ranges (\\SI{0.5}{mW} to \\SI{4.0}{mW})$\\otimes$(\\SI{1.5d12}{cm\\tothe{-3}} to \\SI{1.3d13}{cm\\tothe{-3}}), covering the full practical range and into the strongly-perturbed regime. We show that in these conditions squeezing improves the trade-off between statistical noise and systematic shifts, a new kind of quantum advantage.

  12. High resolution spectroscopy of ultracool M dwarfs

    E-Print Network [OSTI]

    I. Neill Reid; J. Davy Kirkpatrick; J. Liebert; J. E. Gizis; C. C. Dahn; D. G. Monet

    2002-04-17

    (abridged) We present high-resolution echelle spectroscopy of a photometricaly-selected sample if thirty-nine dwarfs with spectral types between M6.5 and L0.5. Two stars, 2MASSI 0253202+271333 and 2MASSW 0952219-192431, are double-lined spectroscopic binaries. We have used our observations to search for Li I 6708 A absorption, characteristic of sub-stellar mass; estimate the level of chromospheric activity through measurement of H-alpha emission fluxes; measure rotational velocities via line broadening; and determine radial velocities and Galactic space motions. Two dwarfs have strong lithium absorption, the previously-known brown dwarf, LP 944-20, and 2MASSI J0335020+234235, which we identify as a probable 0.06 M_sun brown dwarf, age ~1 Gyr. We have investigated the prospect of using the observed frequency of lithium absorption amongst ultracool M dwarfs (M7 to M9.5) as a probe of the initial mass function. The available observations are difficult to reconcile with Salpeter-like power-law mass functions (alpha > 2) for masses below 0.1M_Sun. A comparison between the rotational velocities and -alpha fluxes shows no evidence for significant correlation. Velocity dispersions are significantly lower than those measured for nearby M dwarfs, but show remarkable similarity to results for earlier-type emission-line (dMe) dwarfs. The latter are generally assigned ages of less than ~3 Gyrs.

  13. Linear optics, Raman scattering, and spin noise spectroscopy

    E-Print Network [OSTI]

    Glazov, M M

    2015-01-01

    Spin noise spectroscopy (SNS) is a new method for studying magnetic resonance and spin dynamics based on measuring the Faraday rotation noise. In strong contrast with methods of nonlinear optics, the spectroscopy of spin noise is considered to be essentially nonperturbative. Presently, however, it became clear that the SNS, as an optical technique, demonstrates properties lying far beyond the bounds of conventional linear optics. Specifically, the SNS shows dependence of the signal on the light power density, makes it possible to penetrate inside an inhomogeneously broadened absorption band and to determine its homogeneous width, allows one to realize an effective pump-probe spectroscopy without any optical nonlinearity, etc. This may seem especially puzzling when taken into account that SNS can be considered just as a version of Raman spectroscopy, which is known to be deprived of such abilities. In this paper, we clarify this apparent inconsistency.

  14. Quantitative biological Raman spectroscopy for non-invasive blood analysis

    E-Print Network [OSTI]

    Shih, Wei-Chuan

    2007-01-01

    The long term goal of this project is the measurement of clinically-relevant analytes in the blood tissue matrix of human subjects using near-infrared Raman spectroscopy, with the shorter term research directed towards ...

  15. Early diagnosis of cancer using light scattering spectroscopy

    E-Print Network [OSTI]

    Backman, Vadim, 1973-

    2001-01-01

    This thesis presents a novel optical technique, light scattering spectroscopy (LSS), developed for quantitative characterization of tissue morphology as well as in vivo detection and diagnosis of the diseases associated ...

  16. Electrochemical Impedance Spectroscopy using adjustable nanometer-gap electrodes

    E-Print Network [OSTI]

    Ma, Hongshen, 1978-

    2007-01-01

    Electrochemical Impedance Spectroscopy (EIS) is a simple yet powerful chemical analysis technique for measuring the electrical permittivity and conductivity of liquids and gases. Presently, the limiting factor for using ...

  17. Surface enhanced Raman spectroscopy on a flat graphene surface

    E-Print Network [OSTI]

    Xu, Weigao

    Surface enhanced Raman spectroscopy (SERS) is an attractive analytical technique, which enables single-molecule sensitive detection and provides its special chemical fingerprints. During the past decades, researchers have ...

  18. Impedance Spectroscopy Systems Suitable for Biomedical Cell Impedance Measurement 

    E-Print Network [OSTI]

    Huang, Hao

    2013-06-03

    Impedance spectroscopy (IS) is an important technique for monitoring and detection of biomaterials. In order to enable point-of-care systems, low-cost IS systems capable of rapidly measuring a wide range of biomaterials ...

  19. Radio-frequency spectroscopy of ultracold atomic Fermi gases

    E-Print Network [OSTI]

    Schirotzek, Andre

    2010-01-01

    This thesis presents experiments investigating the phase diagram of ultracold atomic Fermi gases using radio-frequency spectroscopy. The tunability of many experimental parameters including the temperature, the interparticle ...

  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. Photoinduced phase transitions studied by femtosecond single-shot spectroscopy

    E-Print Network [OSTI]

    Shin, Taeho

    2010-01-01

    Single-shot femtosecond spectroscopy has been developed and employed for the study of phase transitions of solid-state materials. Using two crossed echelons, a two dimensional spatial delay gradient was generated across a ...

  2. Crystallization Kinetics of Thermosensitive Colloids Probed by Transmission Spectroscopy

    E-Print Network [OSTI]

    Wu, Jianzhong

    Crystallization Kinetics of Thermosensitive Colloids Probed by Transmission Spectroscopy Shijun hard spheres, soft spheres, and PNIPAM spheres. Introduction Crystallization of colloidal systems systems.1-15 In recent years, colloidal crystals have been used extensively for the fabrication

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

    Office of Scientific and Technical Information (OSTI)

    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:...

  4. Detection of integrins using surface enhanced raman spectroscopy 

    E-Print Network [OSTI]

    Gant, Virgil Alexander

    2005-08-29

    changes of integrins on the surface of a cell maybe possible by developing a combined device such as an atomic force microscope (AFM) and surface enhanced Raman spectroscopy (SERS) system. However, the focus of this research is to first determine...

  5. Fourier Transform Infrared Spectroscopy for Process Monitoring and Control 

    E-Print Network [OSTI]

    Solomon, P. R.; Carangelo, M. D.; Carangelo, R. M.

    1994-01-01

    This paper discusses recent applications of FT-IR spectroscopy to measure gas concentrations and temperatures, and particle sizes. Advances in hardware are discussed and results for field tests in pulp and paper and utility boilers are presented....

  6. Staff Research Physicist (X-Ray Spectroscopy) | Princeton Plasma...

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

    position to work on X-ray spectroscopy, atomic physics, X-ray instrumentation, and high energy density physics. Near-term research goals include participating in the design,...

  7. Quenched hadron spectroscopy with improved staggered quark action

    E-Print Network [OSTI]

    MILC Collaboration; Claude Bernard; Tom Blum; Thomas A. DeGrand; Carleton DeTar; Steven Gottlieb; Urs M. Heller; James Hetrick; Craig McNeile; K. Rummukainen; Bob Sugar; Doug Toussaint

    1997-12-11

    We investigate light hadron spectroscopy with an improved quenched staggered quark action. We compare the results obtained with an improved gauge plus an improved quark action, an improved gauge plus standard quark action, and the standard gauge plus standard quark action. Most of the improvement in the spectroscopy results is due to the improved gauge sector. However, the improved quark action substantially reduces violations of Lorentz invariance, as evidenced by the meson dispersion relations.

  8. Mercury dimer spectroscopy and an Einstein-Podolsky-Rosen experiment 

    E-Print Network [OSTI]

    Qu, Xinmei

    2009-05-15

    SPECTROSCOPY AND AN EINSTEIN-PODOLSKY-ROSEN EXPERIMENT A Dissertation by XINMEI QU Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY... August 2008 Major Subject: Physics MERCURY DIMER SPECTROSCOPY AND AN EINSTEIN-PODOLSKY-ROSEN EXPERIMENT A Dissertation by XINMEI QU Submitted to the Office of Graduate Studies of Texas A&M University in partial...

  9. Chemical Shifts in X-ray and Photo-Electron Spectroscopy: A Historical review

    E-Print Network [OSTI]

    Lindgren, Ingvar

    Chemical Shifts in X-ray and Photo-Electron Spectroscopy: A Historical review Ingvar Lindgren 1 Introduction 2 2 Chemical shift in X-ray spectroscopy 2 2.1 Discovery of the chemical shift in X-ray spectroscopy . . . . . . . . . . . . . 3 2.2 Interpretation of the chemical shift in X-ray spectroscopy

  10. Exoplanet characterization with long slit spectroscopy

    E-Print Network [OSTI]

    Arthur Vigan; Maud Langlois; Claire Moutou; Kjetil Dohlen

    2008-08-28

    Extrasolar planets observation and characterization by high contrast imaging instruments is set to be a very important subject in observational astronomy. Dedicated instruments are being developed to achieve this goal with very high efficiency. In particular, full spectroscopic characterization of low temperature planetary companions is an extremely important milestone. We present a new data analysis method for long slit spectroscopy (LSS) with coronagraphy, which allows characterization of planetary companions of low effective temperature. In a speckle-limited regime, this method allows an accurate estimation and subtraction of the scattered starlight, to extract a clean spectrum of the planetary companion. We performed intensive LSS simulations with IDL/CAOS to obtain realistic spectra of low (R=35) and medium (R=400) resolution in the J, H, and K bands. The simulated spectra were used to test our method and estimate its performance in terms of contrast reduction and extracted spectra quality. Our simulations are based on a software package dedicated to the development of SPHERE, a second generation instrument for the ESO-VLT. Our method allows a contrast reduction of 0.5 to 2.0 magnitudes compared to the coronagraphic observations. For M0 and G0 stars located at 10 pc, we show that it would lead to the characterization of companions with Teff of 600 K and 900 K respectively, at angular separations of 1.0 as. We also show that errors in the wavelength calibration can produce significant errors in the characterization, and must therefore be minimized as much as possible.

  11. 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).

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. Analysis Tools for Next-Generation Hadron Spectroscopy Experiments

    E-Print Network [OSTI]

    M. Battaglieri; B. J. Briscoe; A. Celentano; S. -U. Chung; A. D'Angelo; R. De Vita; M. Döring; J. Dudek; S. Eidelman; S. Fegan; J. Ferretti; A. Filippi; G. Fox; G. Galata; H. Garcia-Tecocoatzi; D. I. Glazier; B. Grube; C. Hanhart; M. Hoferichter; S. M. Hughes; D. G. Ireland; B. Ketzer; F. J. Klein; B. Kubis; B. Liu; P. Masjuan; V. Mathieu; B. McKinnon; R. Mitchell; F. Nerling; S. Paul; J. R. Pelaez; J. Rademacker; A. Rizzo; C. Salgado; E. Santopinto; A. V. Sarantsev; T. Sato; T. Schlüter; M. L. L. da Silva; I. Stankovic; I. Strakovsky; A. Szczepaniak; A. Vassallo; N. K. Walford; D. P. Watts; L. Zana

    2015-03-30

    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. Spectroscopy and reactions of vibrationally excited transient molecules

    SciTech Connect (OSTI)

    Dai, H.L. [Univ. of Pennsylvania, Philadelphia (United States)

    1993-12-01

    Spectroscopy, energy transfer and reactions of vibrationally excited transient molecules are studied through a combination of laser-based excitation techniques and efficient detection of emission from the energized molecules with frequency and time resolution. Specifically, a Time-resolved Fourier Transform Emission Spectroscopy technique has been developed for detecting dispersed laser-induced fluorescence in the IR, visible and UV regions. The structure and spectroscopy of the excited vibrational levels in the electronic ground state, as well as energy relaxation and reactions induced by specific vibronic excitations of a transient molecule can be characterized from time-resolved dispersed fluorescence in the visible and UV region. IR emissions from highly vibrational excited levels, on the other hand, reveal the pathways and rates of collision induced vibrational energy transfer.

  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. Single electron detection and spectroscopy via relativistic cyclotron radiation

    E-Print Network [OSTI]

    D. M. Asner; R. F. Bradley; L. de Viveiros; P. J. Doe; J. L. Fernandes; M. Fertl; E. C. Finn; J. A. Formaggio; D. Furse; A. M. Jones; J. N. Kofron; B. H. LaRoque; M. Leber; E. L. McBride; M. L. Miller; P. Mohanmurthy; B. Monreal; N. S. Oblath; R. G. H. Robertson; L. J Rosenberg; G. Rybka; D. Rysewyk; M. G. Sternberg; J. R. Tedeschi; T. Thummler; B. A. VanDevender; N. L. Woods

    2015-05-01

    It has been understood since 1897 that accelerating charges must 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 spec- trometer. We observe the cyclotron radiation emitted by individual magnetically-trapped electrons that are produced with mildly-relativistic energies by a gaseous radioactive source. The relativistic shift in the cyclotron frequency permits a precise electron energy measurement. Precise beta elec- tron 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 demonstrates a fundamentally new approach to precision beta spectroscopy for future neutrino mass experiments.

  1. 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.

  2. Infrared absorption spectroscopy and chemical kinetics of free radicals

    SciTech Connect (OSTI)

    Curl, R.F.; Glass, G.P. [Rice Univ., Houston, TX (United States)

    1993-12-01

    This research is directed at the detection, monitoring, and study of chemical kinetic behavior by infrared absorption spectroscopy of small free radical species thought to be important intermediates in combustion. During the last year, infrared kinetic spectroscopy using excimer laser flash photolysis and color-center laser probing has been employed to study the high resolution spectrum of HCCN, the rate constant of the reaction between ethynyl (C{sub 2}H) radical and H{sub 2} in the temperature region between 295 and 875 K, and the recombination rate of propargyl (CH{sub 2}CCH) at room temperature.

  3. Detection of Physiologically Relevant Alcohol Concentrations Using Raman Spectroscopy 

    E-Print Network [OSTI]

    McKay, Joshua L.

    2006-08-16

    . A. Watson, J. P. Wicksted, R. D. Stith, and W. F. March, ?Analysis of metabolites in aqueous solutions by using laser Raman spectroscopy,? Applied Optics, 32-6, 925-929, (1993). 5. A. J. Berger, Y. Wang, and M. S. Feld, ?Rapid, noninvasive... concentration measurements of aqueous biological analytes by near-infrared Raman spectroscopy,? Applied Optics, 35-1, 209-212, (1996). 29 6. A. J. Berger, I. Itzkan, and M. S. Feld, ?Feasibility of measuring blood glucose concentration by near...

  4. Trace metal mapping by laser-induced breakdown spectroscopy

    SciTech Connect (OSTI)

    Kaiser, Jozef [ORNL; Novotny, Dr. Karel [Masaryk University; Hrdlicka, A [Brno University of Technology, Czech Republic; Malina, R [Brno University of Technology, Czech Republic; Hartl, M [Brno University of Technology, Czech Republic; Kizek, R [Mendel University of Brno; Adam, V [Mendel University of Brno

    2012-01-01

    Abstract: Laser-Induced Breakdown Spectroscopy (LIBS) is a sensitive optical technique capable of fast multi-elemental analysis of solid, gaseous and liquid samples. The potential applications of lasers for spectrochemical analysis were developed shortly after its invention; however the massive development of LIBS is connected with the availability of powerful pulsed laser sources. Since the late 80s of 20th century LIBS dominated the analytical atomic spectroscopy scene and its application are developed continuously. Here we review the utilization of LIBS for trace elements mapping in different matrices. The main emphasis is on trace metal mapping in biological samples.

  5. 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.

  6. Synchrotron Radiation Photoemission Spectroscopic Study of Band Offsets and Interface Self-cleaning by Atomic Layer Deposited HfO2 on In0.53Ga0.47As and In0.52Al0.48As

    SciTech Connect (OSTI)

    Kobayashi, Masaharu; /SLAC, SSRL; Chen, P.T.; Sun, Y.; Goel, N.; Majhi, P.; Garner, M; Tsai, W.; Pianetta, P.; Nishi, Y.; /SLAC, SSRL

    2008-10-31

    The Synchrotron Radiation Photoemission Spectroscopic (SRPES) study was conducted to (a) investigate the surface chemistry of In{sub 0.53}Ga{sub 0.47}As and In{sub 0.52}Al{sub 0.48}As post chemical and thermal treatments, (b) construct band diagram and (c) investigate the interface property of HfO{sub 2}/In{sub 0.53}Ga{sub 0.47}As and HfO{sub 2}/In{sub 0.52}Al{sub 0.48}As. Dilute HCl and HF etch remove native oxides on In{sub 0.53}Ga{sub 0.47}As and In{sub 0.52}Al{sub 0.47}As, whereas in-situ vacuum annealing removes surface arsenic pile-up. After the atomic layer deposition of HfO{sub 2}, native oxides were considerably reduced compared to that in as-received epi-layers, strongly suggesting the self-clean mechanism. Valence and conduction band offsets are measured to be 3.37 {+-} 0.1eV, 1.80 {+-} 0.3eV for In{sub 0.53}Ga{sub 0.47}As and 3.00 {+-} 0.1eV, 1.47 {+-} 0.3eV for In{sub 0.52}Al{sub 0.47}As, respectively.

  7. Wavelength modulation spectroscopy using novel mechanical light chopper blade designs

    E-Print Network [OSTI]

    Ghosh, Sandip

    Wavelength modulation spectroscopy using novel mechanical light chopper blade designs Jayeeta 23 May 2005; published online 21 July 2005 We describe two mechanical light chopper blade designs wavelength for positive grating orders. Our two designs, the alternating double-slot blade and the vertical

  8. New Frontiers in Solar Physics: Broadband Imaging Spectroscopy with the

    E-Print Network [OSTI]

    , the solar panel of the AASC recommended an integrated suite of instrumentation designed to meetNew Frontiers in Solar Physics: Broadband Imaging Spectroscopy with the Frequency Agile Solar and other astrophysical objects and processes. Outstanding problems in solar physics include the magnetic

  9. Amyloid Oligomer Formation Probed by Water Proton Magnetic Resonance Spectroscopy

    E-Print Network [OSTI]

    Berry, R. Stephen

    Amyloid Oligomer Formation Probed by Water Proton Magnetic Resonance Spectroscopy J. H. Walton, R, Chicago, Illinois; and § Department of Pharmacology, University of California, Davis, California ABSTRACT Formation of amyloid oligomers, the most toxic species of amyloids in degenerative diseases, is critically

  10. 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

  11. Use of gamma spectroscopy for neutronic analysis of LMFBR Blankets

    E-Print Network [OSTI]

    Kang, Ch?ang-sun

    It was the purpose of the present investigation to extend and apply Ge(Li) gamma-ray spectroscopy to the study of fast reactor blankets. The focal point for this research was the Blanket Test Facility at the MITR and Blanket ...

  12. Charm and Charmonium Spectroscopy in BaBar

    SciTech Connect (OSTI)

    Negrini, M.; /Ferrara U.

    2008-02-06

    The BABAR experiment at the PEP-II B-factory offers excellent opportunities in charm and charmonium spectroscopy. The recent observation of new states in the D{sub s} and in the charmonium mass regions revived the interest in this field. Recent BABAR results are presented.

  13. 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.

  14. Thermal infrared emission spectroscopy of the pyroxene mineral series

    E-Print Network [OSTI]

    Hamilton, Victoria E.

    Thermal infrared emission spectroscopy of the pyroxene mineral series Victoria E. Hamilton within the two structural groups, as well as minerals within solid solution series. The exact number of reststrahlen features observed and their positions are dependent on mineral structure and cation occupancy

  15. Cysteine engineering of polyproteins for single-molecule force spectroscopy

    E-Print Network [OSTI]

    Dietz, Hendrik

    polyprotein construction. The basic concept of cysteine engineering of polyproteins is out- lined in Figure 1Cysteine engineering of polyproteins for single- molecule force spectroscopy Hendrik Dietz, Morten. We describe in detail the method to construct polyproteins with precisely controlled linkage

  16. Skin cancer detection by oblique-incidence diffuse reflectance spectroscopy 

    E-Print Network [OSTI]

    Smith, Elizabeth Brooks

    2009-05-15

    Skin cancer is the most common form of cancer and it is on the rise. If skin cancer is diagnosed early enough, the survival rate is close to 90%. Oblique-incidence diffuse reflectance (OIR) spectroscopy offers a technology that may be used...

  17. Spectroscopy of He 2 Floating on the Liquid Helium Surface

    E-Print Network [OSTI]

    Northby, Jan A.

    Spectroscopy of He 2 Floating on the Liquid Helium Surface Chih-Ching Hu, Raghuram Petluri, Jan A helium molecules produced in electron bombarded helium nanodroplets subsequently are detached by infrared highly sensitive detection of the absorption spectrum. Recent experiments utilize a new tunable infrared

  18. Postdoc Position in Microfluidics and Single Cell Raman Spectroscopy

    E-Print Network [OSTI]

    Horn, Matthias

    Postdoc Position in Microfluidics and Single Cell Raman Spectroscopy Department of Microbial and Environmental Microfluidics Group (http://web.mit.edu/romanstocker) Department of Civil & Environmental (junior or senior) with strong expertise in microfluidics and an interest in applying it to microbial

  19. Broadband microwave imaging spectroscopy with a solardedicated array

    E-Print Network [OSTI]

    Broad­band microwave imaging spectroscopy with a solar­dedicated array T.S. Bastian a , D.E. Gary b of Astronomy, University of Maryland, College Park, MD 20742 d Solar Astronomy 264­33, Caltech, Pasadena, CA the thermal structure of the solar atmosphere, and to study energy release and particle energization

  20. Multidimensional femtosecond spectroscopies of vibrational motions in liquids: Semiclassical expansion

    E-Print Network [OSTI]

    Mukamel, Shaul

    for nuclear wave packets, even when the system itself may be highly nonclassical. Two sources and vibrational anharmonicities--are identified. Formal analogy between the present equations and the time in nuclear magnetic resonance spectroscopy4 to provide invaluable information on the struc- ture and dynamics

  1. 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...

  2. A computational approach to spectroscopy of molecular systems : modeling, prediction, and design

    E-Print Network [OSTI]

    Horning, Andrew D. (Andrew Davis)

    2015-01-01

    This thesis describes a series of approaches for modeling spectroscopy of molecular systems in aqueous environments, focusing on proton transfer, water dynamics, and hydrogen bonding interactions. The spectroscopy motivating ...

  3. X-Ray Spectroscopy of the Mn(4) Ca Cluster in the Water-Oxidation...

    Office of Scientific and Technical Information (OSTI)

    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...

  4. Development of multimodal spectroscopy for the detection of vulnerable atherosclerotic plaques

    E-Print Network [OSTI]

    Š?epanovi?, Obrad R., 1980-

    2008-01-01

    The combination of reflectance, fluorescence, and Raman spectroscopy - which is termed multimodal spectroscopy (MMS) - provides complementary and depth-sensitive information about tissue composition. As such, MMS can provide ...

  5. Geophysical applications of nuclear resonant spectroscopy Wolfgang Sturhahn and Jennifer M. Jackson*

    E-Print Network [OSTI]

    Jackson, Jennifer M.

    Geophysical applications of nuclear resonant spectroscopy Wolfgang Sturhahn and Jennifer M. Jackson summarize recent developments of nuclear resonant spectroscopy methods like nuclear resonant inelastic x important information on valence, spin state, and magnetic ordering. Both methods use a nuclear resonant

  6. 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...

  7. The structure of langmuir monolayers probed with vibrational sum frequency spectroscopy 

    E-Print Network [OSTI]

    Gurau, Marc Cory

    2005-08-29

    structure have been examined with vibrational sum frequency spectroscopy (VSFS). This second order nonlinear optical spectroscopy is particularly well suited for simultaneous investigations of the monolayer and the associated water structure...

  8. Development of High-Throughput Microfluidic Impedance Spectroscopy Platform for Analyzing Microdroplets in Droplet Microfluidic System 

    E-Print Network [OSTI]

    Sobahi, Nebras MohammedKamal A.

    2014-07-22

    This thesis presents the development of a high-throughput microfluidic impedance spectroscopy platform for electrically detecting analyzing impedance measurements of non-contact and label free microdroplets. This microfluidic impedance spectroscopy...

  9. In situ characterization of soil properties using visible near-infrared diffuse reflectance spectroscopy 

    E-Print Network [OSTI]

    Waiser, Travis Heath

    2007-09-17

    Diffuse reflectance spectroscopy (DRS) is a rapid proximal-sensing method that is being used more and more in laboratory settings to measure soil properties. Diffuse reflectance spectroscopy research that has been completed in laboratories shows...

  10. 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.

  11. X-ray line polarization spectroscopy of Li-like satellite line...

    Office of Scientific and Technical Information (OSTI)

    United States Language: English Subject: 74; ANISOTROPY; DISTRIBUTION FUNCTIONS; ELECTRONS; KINETICS; LASERS; PLASMA; POLARIZATION; PULSES; SATELLITES; SPECTRA; SPECTROSCOPY...

  12. Methods for measurement of heterogeneous materials with laser-induced breakdown spectroscopy (LIBS)

    E-Print Network [OSTI]

    Effenberger, Andrew Jay

    2009-01-01

    pulse laser-induced breakdown spectroscopy ICCD – intensified charge-coupled device LSC – laser-supported combustion

  13. 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.

  14. Discrepancies between isotope ratio infrared spectroscopy and isotope ratio mass spectrometry for the

    E-Print Network [OSTI]

    Goldsmith, Greg

    -axis integrated cavity output spectroscopy (OA-ICOS, Los Gatos Research) and wavelength-scanned cavity ring

  15. Applications of laser-induced gratings to spectroscopy and dynamics

    SciTech Connect (OSTI)

    Rohlfing, E.A. [Sandia National Laboratories, Livermore, CA (United States)

    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.

  16. 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.

  17. Momentum-resolved spectroscopy of a Fermi liquid

    E-Print Network [OSTI]

    Elmer V. H. Doggen; Jami J. Kinnunen

    2014-11-26

    We consider a recent momentum-resolved radio-frequency spectroscopy experiment, in which Fermi liquid properties of a strongly interacting atomic Fermi gas were studied. Here we show that by extending the Brueckner-Goldstone model, we can formulate a theory that goes beyond basic mean-field theories and that can be used for studying spectroscopies of dilute atomic gases in the strongly interacting regime. The model hosts well-defined quasiparticles and works across a wide range of temperatures and interaction strengths. The theory provides excellent qualitative agreement with the experiment. Comparing the predictions of the present theory with the mean-field Bardeen-Cooper-Schrieffer theory yields insights into the role of pair correlations, Tan's contact, and the Hartree mean-field energy shift.

  18. Photothermal cantilever deflection spectroscopy of a photosensitive polymer

    SciTech Connect (OSTI)

    Yun, Minhyuk; Lee, Dongkyu; Jung, Namchul; Jeon, Sangmin [Department of Chemical Engineering, Pohang University of Science and Technology, Pohang (Korea, Republic of); Kim, Seonghwan; Chae, Inseok; Thundat, Thomas [Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta T6G 2V4 (Canada)

    2012-05-14

    The mechanical and chemical information of a poly(methyl methacrylate) (PMMA) film on a microcantilever were simultaneously acquired by photothermal cantilever deflection spectroscopy as a function of ultraviolet (UV) irradiation time. Nanomechanical infrared (IR) spectra from the PMMA-coated microcantilever agreed well with the Fourier transform infrared spectroscopy (FTIR) spectra of PMMA on gold-coated silicon wafer. The decreasing intensities of nanomechanical IR peaks represent chemical as well as mechanical information of UV radiation-induced photodegradation processes in the PMMA which cannot be obtained by a conventional FTIR technique. The observed decrease in the resonance frequency of the microcantilever is related to the change in the Young's modulus of the PMMA under UV exposure.

  19. 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.

  20. ?-decay spectroscopy for the r-process nucleosynthesis

    SciTech Connect (OSTI)

    Nishimura, Shunji [RIKEN Nishina Center, Wako, Saitama 351-0198 (Japan); Collaboration: RIBF Decay Collaborations

    2014-05-09

    Series of decay spectroscopy experiments, utilizing of high-purity Ge detectors and double-sided silicon-strip detectors, have been conducted to harvest the decay properties of very exotic nuclei relevant to the r-process nucleosynthesis at the RIBF. The decay properties such as ?-decay half-lives, low-lying states, ?-delayed neutron emissions, isomeric states, and possibly Q{sub ?} of the very neutron-rich nuclei are to be measured to give significant constraints in the uncertainties of nuclear properties for the r-process nucleosynthesis. Recent results of ?? spectroscopy study using in-flight fission of {sup 238}U-beam will be presented together with our future perspectives.

  1. Nuclear magnetic resonance spectroscopy of single subnanoliter ova

    E-Print Network [OSTI]

    Grisi, Marco; Guidetti, Roberto; Harris, Nicola; Boero, Giovanni

    2015-01-01

    Nuclear magnetic resonance (NMR) spectroscopy is, in principle, a promising candidate to study the intracellular chemistry of single microscopic living entities. However, due to sensitivity limitations, NMR experiments were reported only on very few and relatively large single cells down to a minimum volume of 10 nl. Here we show NMR spectroscopy of single ova at volume scales (0.1 and 0.5 nl) where life development begins for a broad variety of animals, humans included. We demonstrate that the sensitivity achieved by miniaturized inductive NMR probes (few pmol of 1H nuclei in some hours at 7 T) is sufficient to observe chemical heterogeneities among subnanoliter ova of tardigrades. Such sensitivities should allow to non-invasively monitor variations of concentrated intracellular compounds, such as glutathione, in single mammalian zygotes.

  2. 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

  3. 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)

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. Photoelectron Spectroscopy of SO3 -at 355 and 266 nm

    E-Print Network [OSTI]

    Continetti, Robert E.

    Photoelectron Spectroscopy of SO3 - at 355 and 266 nm S. Dobrin, B. H. Boo, L. S. Alconcel, and R Photoelectron spectra of SO3 - were recorded at 266 and 355 nm to study photodetachment of the SO3 - anion (2 A1) to the ground state of neutral SO3 (1 A1). A long vibrational progression in the 355 nm spectrum is attributed

  9. 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.

  10. 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.

  11. Bimolecular reaction dynamics from photoelectron spectroscopy of negative ions

    SciTech Connect (OSTI)

    Bradforth, S.E.

    1992-11-01

    The transition state region of a neutral bimolecular reaction may be experimentally investigated by photoelectron spectroscopy of an appropriate negative ion. The photoelectron spectrum provides information on the spectroscopy and dynamics of the short lived transition state and may be used to develop model potential energy surfaces that are semi-quantitative in this important region. The principles of bound {yields} bound negative ion photoelectron spectroscopy are illustrated by way of an example: a full analysis of the photoelectron bands of CN{sup {minus}}, NCO{sup {minus}} and NCS{sup {minus}}. Transition state photoelectron spectra are presented for the following systems Br + HI, Cl + HI, F + HI, F + CH{sub 3}0H,F + C{sub 2}H{sub 5}OH,F + OH and F + H{sub 2}. A time dependent framework for the simulation and interpretation of the bound {yields} free transition state photoelectron spectra is subsequently developed and applied to the hydrogen transfer reactions Br + HI, F + OH {yields} O({sup 3}P, {sup 1}D) + HF and F + H{sub 2}. The theoretical approach for the simulations is a fully quantum-mechanical wave packet propagation on a collinear model reaction potential surface. The connection between the wavepacket time evolution and the photoelectron spectrum is given by the time autocorrelation function. For the benchmark F + H{sub 2} system, comparisons with three-dimensional quantum calculations are made.

  12. 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

  13. One-Dimensional Helical Transport in Topological Insulator Nanowire Interferometers

    E-Print Network [OSTI]

    Cui, Yi

    a gateway to generate unusual phases and particles made of the helical surface electrons, proposing new- resolved photoemission spectroscopy (ARPES) and scanning tunneling microscopy (STM).5-12 Electronic device

  14. 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.

  15. Improvements to TITAN's Mass Measurement and Decay Spectroscopy Capabilities

    E-Print Network [OSTI]

    D. Lascar; A. A. Kwiatkowski; U. Chowdhury; A. Finlay; A. T. Gallant; M. Good; R. Klawitter; B. Kootte; K. G. Leach; A. Lennarz; E. Leistenschneider; B. E. Schultz; R. Schupp; D. A. Short; C. Andreoiu; J. Dilling; G. Gwinner

    2015-08-27

    The study of nuclei farther from the valley of $\\beta$-stability goes hand-in-hand with shorter-lived nuclei produced in smaller abundances than their more stable counterparts. The measurement, to high precision, of nuclear masses therefore requires innovations in technique in order to keep up. TRIUMF's Ion Trap for Atomic and Nuclear science (TITAN) facility deploys three ion traps, with a fourth in the commissioning phase, to perform and support Penning trap mass spectrometry and in-trap decay spectroscopy on some of the shortest-lived nuclei ever studied. We report on recent advances and updates to the TITAN facility since the 2012 EMIS Conference. TITAN's charge breeding capabilities have been improved and in-trap decay spectroscopy can be performed in TITAN's electron beam ion trap (EBIT). Higher charge states can improve the precision of mass measurements, reduce the beam-time requirements for a given measurement, improve beam purity and opens the door to access, via in-trap decay and recapture, isotopes not available from the ISOL method. This was recently demonstrated during TITAN's mass measurement of $^{30}$Al. The EBIT's decay spectroscopy setup was commissioned with a successful branching ratio and half-life measurement of $^{124}$Cs. Charge breeding in the EBIT increases the energy spread of the ion bunch sent to the Penning trap for mass measurement so a new Cooler Penning Trap (CPET), which aims to cool highly charge ions with an electron plasma, is undergoing online commissioning. Already, CPET has demonstrated the trapping and self-cooling of a room-temperature electron plasma which was stored for several minutes. A new detector has been installed inside the CPET magnetic field which will allow for in-magnet charged particle detection.

  16. 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.

  17. 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 ?, 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 thatmore »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.« less

  18. 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.

  19. Evaluation of two-beam spectroscopy as a plasma diagnostic

    SciTech Connect (OSTI)

    Billard, B.D.

    1980-04-01

    A two-beam spectroscopy (TBS) system is evaluated theoretically and experimentally. This new spectroscopic technique uses correlations between components of emitted light separated by a small difference in angle of propagation. It is thus a non-perturbing plasma diagnostic which is shown to provide local (as opposed to line-of-sight averaged) information about fluctuations in the density of light sources within a plasma - information not obtainable by the usual spectroscopic methods. The present design is an improvement on earlier systems proposed in a thesis by Rostler.

  20. The Meson Spectroscopy Program at the Jefferson Laboratory

    SciTech Connect (OSTI)

    Filippi, Alessandro; et. al.,

    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/c^2. 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.

  1. 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.

  2. Hadron Spectroscopy from QCD Robert Edwards Jefferson Lab

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration would likeUniverse (Journalvivo Low-Dose Lowï‚—34 Revision 0August 9, 2012115Hadron Spectroscopy

  3. Microrheology of polyethylene oxide using diffusing wave spectroscopy and single scattering Bivash R. Dasgupta,1

    E-Print Network [OSTI]

    Microrheology of polyethylene oxide using diffusing wave spectroscopy and single scattering Bivash on polyethylene oxide solutions in the semidilute regime using polystyrene beads of varying sizes and surface

  4. Spectroscopy, photo-physics, and time resolved exciton dynamics of GaSe quantum dots

    E-Print Network [OSTI]

    Mirafzal, Hoda

    2011-01-01

    MERCED Spectroscopy, Photo-physics, and Time Resolvedresolve this issue is to photo-select the heterostructuresof particles is first photo-selected by polarized excitation

  5. VUV spectroscopy and photo-processing of astrochemical ices: an experimental study

    E-Print Network [OSTI]

    Kaiser, Ralf I.

    VUV spectroscopy and photo-processing of astrochemical ices: an experimental study Nigel J. Mason environments within our universe has relied critically upon the continuing technological advances

  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. Tunable excitation source for coherent Raman spectroscopy based on a single fiber laser

    E-Print Network [OSTI]

    Adany, Peter; Arnett, David C.; Johnson, Carey K.; Hui, Rongqing

    2011-10-01

    We demonstrate a wavelength tunable optical excitation source for coherent Raman scattering (CRS) spectroscopy based on a single femtosecondfiber laser. Electrically controlled wavelength tuning of Stokes optical pulses ...

  8. Understanding colloidal quantum dot excitation with solution photon correlation fourier spectroscopy

    E-Print Network [OSTI]

    Heathcote, S. Leigh (Stephanie Leigh)

    2015-01-01

    Colloidal quantum dots (CQDs) have useful absorption and emission properties but exist in inhomogenous batches. Solution photon correlation fourier spectroscopy (S-PCFS) combines interferometry with fluorescence correlation ...

  9. Testing and Evaluation Protocol for Spectroscopy-Based Portal Monitors Used for Homeland Security

    E-Print Network [OSTI]

    Testing and Evaluation Protocol for Spectroscopy- Based Portal Monitors Used for Homeland Security................................................................................1 4. Test and evaluation steps .........................................................................................1 5. Recording test results

  10. Anatomy-Based Algorithms for Detecting Oral Cancer Using Reflectance and Fluorescence Spectroscopy

    E-Print Network [OSTI]

    McGee, Sasha

    OBJECTIVES: We used reflectance and fluorescence spectroscopy to noninvasively and quantitatively distinguish benign from dysplastic/malignant oral lesions. We designed diagnostic algorithms to account for differences in ...

  11. Low State, Phase-Resolved IR Spectroscopy of VV Puppis

    E-Print Network [OSTI]

    Steve B. Howell; Thomas E. Harrison; Ryan K. Campbell; France A. Cordova; Paula Szkody

    2005-12-13

    We present phase-resolved low resolution $JHK$ and higher resolution $K$-band spectroscopy of the polar VV Pup. All observations were obtained when VV Pup was in a low accretion state having a K magnitude near 15. The low resolution observations reveal cyclotron emission in the $J$ band during some phases, consistent with an origin near the active 30.5 MG pole on the white dwarf. The secondary in VV Pup appears to be a normal M7V star and we find that the $H$ and $K$ band fluxes are entirely due to this star at all orbital phases during the low accretion state. We use our higher resolution Keck spectroscopy to produce the first $K$-band radial velocity curve for VV Pup. Our orbital solution yields $K_2$=414$\\pm27$ km sec$^{-1}$ and leads to mass estimates of M$_1$=0.73$\\pm$0.05 M$_{\\odot}$ and M$_2$=0.10$\\pm$0.02 M$_{\\odot}$. We find that the mass accretion rates during the normal low states of the polars VV Pup, EF Eri, and EQ Cet are near 10$^{-13}$ M$_{\\odot}$ yr$^{-1}$. The fact that \\.M is not zero in low state polars indicates active secondary stars in these binary systems, including the sub-stellar donor star present in EF Eri.

  12. 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.

  13. The TITAN in-trap decay spectroscopy facility at TRIUMF

    E-Print Network [OSTI]

    K. G. Leach; A. Grossheim; A. Lennarz; T. Brunner; J. R. Crespo López-Urrutia; A. T. Gallant; M. Good; R. Klawitter; A. A. Kwiatkowski; T. Ma; T. D. Macdonald; S. Seeraji; M. C. Simon; C. Andreoiu; J. Dilling; D. Frekers

    2014-11-22

    This article presents an upgraded in-trap decay spectroscopy apparatus which has been developed and constructed for use with TRIUMF's Ion Trap for Atomic and Nuclear science (TITAN). This device consists of an open-access electron-beam ion-trap (EBIT), which is surrounded radially by seven low-energy planar Si(Li) detectors. The environment of the EBIT allows for the detection of low-energy photons by providing backing-free storage of the radioactive ions, while guiding charged decay particles away from the trap centre via the strong (up to 6 T) magnetic field. In addition to excellent ion confinement and storage, the EBIT also provides a venue for performing decay spectroscopy on highly-charged radioactive ions. Recent technical advancements have been able to provide a significant increase in sensitivity for low-energy photon detection, towards the goal of measuring weak electron-capture branching ratios of the intermediate nuclei in the two-neutrino double beta ($2\

  14. 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.

  15. THz time-domain spectroscopy for tokamak plasma diagnostics

    SciTech Connect (OSTI)

    Causa, F.; Zerbini, M.; Buratti, P.; Gabellieri, L.; Pacella, D.; Romano, A.; Tuccillo, A. A.; Tudisco, O. [ASSOCIAZIONE EURATOM ENEA sulla Fusione, C. R. Frascati, via E. Fermi 45, 00044 Frascati (Roma) (Italy); Johnston, M. [Clarendon Laboratory, Department of Physics, University of Oxford, Parks Road, Oxford OX1 3PU (United Kingdom); Doria, A.; Gallerano, G. P.; Giovenale, E. [ENEA C.R. Frascati UTAPRAD, via E. Fermi 45, 00044 Frascati (Roma) (Italy)

    2014-08-21

    The technology is now becoming mature for diagnostics using large portions of the electromagnetic spectrum simultaneously, in the form of THz pulses. THz radiation-based techniques have become feasible for a variety of applications, e.g., spectroscopy, imaging for security, medicine and pharmaceutical industry. In particular, time-domain spectroscopy (TDS) is now being used also for plasma diagnostics in various fields of application. This technique is promising also for plasmas for fusion applications, where plasma characteristics are non-uniform and/or evolve during the discharge This is because THz pulses produced with femtosecond mode-locked lasers conveniently span the spectrum above and below the plasma frequency and, thus, can be used as very sensitive and versatile probes of widely varying plasma parameters. The short pulse duration permits time resolving plasma characteristics while the large frequency span permits a large dynamic range. The focus of this work is to present preliminary experimental and simulation results demonstrating that THz TDS can be realistically adapted as a versatile tokamak plasma diagnostic technique.

  16. Search for ultralight scalar dark matter with atomic spectroscopy

    E-Print Network [OSTI]

    Ken Van Tilburg; Nathan Leefer; Lykourgos Bougas; Dmitry Budker

    2015-04-08

    We report new limits on ultralight scalar dark matter (DM) with dilaton-like couplings to photons that can induce oscillations in the fine-structure constant alpha. Atomic dysprosium exhibits an electronic structure with two nearly degenerate levels whose energy splitting is sensitive to changes in alpha. Spectroscopy data for two isotopes of dysprosium over a two-year span is analyzed for coherent oscillations with angular frequencies below 1 rad/s. No signal consistent with a DM coupling is identified, leading to new constraints on dilaton-like photon couplings over a wide mass range. Under the assumption that the scalar field comprises all of the DM, our limits on the coupling exceed those from equivalence-principle tests by up to 4 orders of magnitude for masses below 3 * 10^-18 eV. Excess oscillatory power, inconsistent with fine-structure variation, is detected in a control channel, and is likely due to a systematic effect. Our atomic spectroscopy limits on DM are the first of their kind, and leave substantial room for improvement with state-of-the-art atomic clocks.

  17. 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.

  18. Infrared and photoluminescence spectroscopy of p-doped self-assembled Ge dots on Si

    E-Print Network [OSTI]

    Rokhinson, Leonid

    Infrared and photoluminescence spectroscopy of p-doped self-assembled Ge dots on Si L. P and photoluminescence PL spectroscopy of self-assembled Ge dots grown on Si 100 by molecular beam epitaxy. PL spectra show a transition from two- to three-dimensional growth as the Ge thickness exceeds 7 Å. The sum

  19. Mapping boron in silicon solar cells using electron energy-loss spectroscopy

    E-Print Network [OSTI]

    Dunin-Borkowski, Rafal E.

    Mapping boron in silicon solar cells using electron energy-loss spectroscopy M Duchamp1 , C B 3 ECN Solar Energy, P.O. Box 1, NL-1755 ZG Petten, The Netherlands 4 CEA-Leti, MINATEC Campus, 17-mail: martial.duchamp@cen.dtu.dk Abstract. Electron energy-loss spectroscopy (EELS) is used to study the B

  20. Stimulated coherent anti-Stokes Raman spectroscopy (CARS) resonances originate from double-slit

    E-Print Network [OSTI]

    Mukamel, Shaul

    Stimulated coherent anti-Stokes Raman spectroscopy (CARS) resonances originate from double January 21, 2010 (received for review September 3, 2009) Coherent anti-Stokes Raman spectroscopy (CARS with re- spect to pulse parameters. CARS microscopy pulse shaping ultrafast spectroscpy Coherent Raman

  1. Keck/HIRES Spectroscopy of Four Candidate Solar Twins Jeremy R. King

    E-Print Network [OSTI]

    King, Jeremy

    terrestrial exoplanets around solar analogs remains a natural one given the existence of our own solar systemKeck/HIRES Spectroscopy of Four Candidate Solar Twins Jeremy R. King Department of Physics-0978 sschule@ces.clemson.edu ABSTRACT We use high S/N, high-resolution Keck/HIRES spectroscopy of 4 solar twin

  2. Keck/HIRES Spectroscopy of Four Candidate Solar Twins Jeremy R. King

    E-Print Network [OSTI]

    King, Jeremy

    terrestrial exoplanets around solar analogs remains a natural one given the existence of our own solar systemKeck/HIRES Spectroscopy of Four Candidate Solar Twins Jeremy R. King Department of Physics­0978 sschule@ces.clemson.edu ABSTRACT We use high S/N, high­resolution Keck/HIRES spectroscopy of 4 solar twin

  3. Low-temperature Scanning Tunneling Spectroscopy of Semiconductor Surfaces R. M. Feenstra1

    E-Print Network [OSTI]

    Feenstra, Randall

    1 Low-temperature Scanning Tunneling Spectroscopy of Semiconductor Surfaces R. M. Feenstra1 Low-temperature scanning tunneling spectroscopy measurements on semiconductor surface are described that measurements at low temperatures have been conducted. Most notably, discrete accumulation layer states have

  4. The radio waves and thermal electrostatic noise spectroscopy (SORBET) experiment on BEPICOLOMBO/MMO/PWI

    E-Print Network [OSTI]

    Aulanier, Guillaume

    The radio waves and thermal electrostatic noise spectroscopy (SORBET) experiment on BEPICOLOMBO spectrometer designed for the radio and Plasma Waves Instrument onboard BepiColombo/Mercury Magnetospheric noise spectroscopy; Radio and plasma waves; Spacecraft instrumentation; BepiColombo/MMO 0273-1177/$30 Ó

  5. On Impedance Spectroscopy Contribution to Failure Diagnosis in Wind Turbine Generators

    E-Print Network [OSTI]

    Boyer, Edmond

    On Impedance Spectroscopy Contribution to Failure Diagnosis in Wind Turbine Generators Mohamed Becherif1 , El Houssin El Bouchikhi2 and Mohamed Benbouzid2 Abstract ­ Wind turbines proliferation impedance spectroscopy contribution to the failure diagnosis of doubly-fed induction generator-based wind

  6. Far-Infrared Dielectric Properties of Polar Liquids Probed by Femtosecond Terahertz Pulse Spectroscopy

    E-Print Network [OSTI]

    . These spectra have been measured with femtosecond terahertz pulse transmission spectroscopy. These liquids demonstrate here that transmission spectroscopy with fs THz pulses is an efficient way to obtain the FIR with similar duration, but in this case its spectral range starts at zero frequency (dc), rather than being

  7. INVESTIGATIONS ON NUCLEAR SPECTROSCOPY AT THE REACTOR AND THEIR APPLICATIONS1

    E-Print Network [OSTI]

    Titov, Anatoly

    1 INVESTIGATIONS ON NUCLEAR SPECTROSCOPY AT THE REACTOR AND THEIR APPLICATIONS1 I.A. Kondurov , E. However the first work on nuclear spectroscopy was carried out before the reactor was launched; namely.M. Korotkikh, Yu.E. Loginov, V.V. Martynov Introduction Physical launch of the WWR-M reactor in the branch

  8. Characterization of hydrocarbon and mixed layers in TEXTOR by laser induced ablation spectroscopy

    E-Print Network [OSTI]

    Giesen, Thomas

    Characterization of hydrocarbon and mixed layers in TEXTOR by laser induced ablation spectroscopy) 014026 (4pp) doi:10.1088/0031-8949/2011/T145/014026 Characterization of hydrocarbon and mixed layers systematic laser-induced ablation spectroscopy (LIAS) measurements carried out on various surface layers

  9. Monitoring Nonadiabatic Dynamics of the RNA Base Uracil by UV Pump-IR Probe Spectroscopy

    E-Print Network [OSTI]

    Mukamel, Shaul

    Monitoring Nonadiabatic Dynamics of the RNA Base Uracil by UV Pump-IR Probe Spectroscopy Benjamin P dynamics simulations of the UV pump-IR probe signal of the pyrimidine nucleobase uracil using a novel or visible pump-probe or photoelectron spectroscopy offer a high sub-100 fs temporal resolution.9

  10. X-ray Spectroscopy of Massive Star Winds: Shocks, Mass-Loss Rates, and Clumping

    E-Print Network [OSTI]

    Cohen, David

    X-ray Spectroscopy of Massive Star Winds: Shocks, Mass-Loss Rates, and Clumping David Cohen X-rays A. wind-shock physics B. wind absorption: wind mass-loss rate C. with H-alpha: wind clumping Chandra resolved X-ray line profile spectroscopy of O star winds #12;Prior to 2000: only low-resolution X

  11. Metal binding in proteins: machine learning complements X-ray absorption spectroscopy

    E-Print Network [OSTI]

    Passerini, Andrea

    Metal binding in proteins: machine learning complements X-ray absorption spectroscopy Marco Lippi1 for the identification of metalloproteins and metal binding sites on a genome scale. An extensive evaluation conducted in combination with X- ray absorption spectroscopy shows the great potentiality of the approach. 1 Metal binding

  12. Measurement of uranium enrichment by gamma spectroscopy: result of an experimental design

    E-Print Network [OSTI]

    PAPER Measurement of uranium enrichment by gamma spectroscopy: result of an experimental design Gamma spectroscopy is commonly used in nuclear safeguards to measure uranium enrichment. An experimental design has been carried out for the measurement of uranium enrichment using this technique with different

  13. Spectroscopy of jet-cooled YCu Caleb A. Arrington, Dale J. Brugh, and Michael D. Morse

    E-Print Network [OSTI]

    Morse, Michael D.

    Spectroscopy of jet-cooled YCu Caleb A. Arrington, Dale J. Brugh, and Michael D. Morse Department spectra of jet-cooled diatomic YCu have been recorded using resonant two-photon ionization spectroscopy a nearly continuous adsorption spectrum, even in the jet-cooled molecules. Another study of the mixed early

  14. Quasiparticle interference, quasiparticle interactions, and the origin of the charge density wave in 2H-NbSe?

    SciTech Connect (OSTI)

    Arguello, C. J. [Columbia Univ., New York, NY (United States); Valla, T. [Brookhaven National Lab. (BNL), Upton, NY (United States); Rosenthal, E. P. [Columbia Univ., New York, NY (United States); Andrade, E. F. [Columbia Univ., New York, NY (United States); Jin, W. [Columbia Univ., New York, NY (United States); Yeh, P. C. [Columbia Univ., New York, NY (United States); Zaki, N. [Columbia Univ., New York, NY (United States); Jia, S. [Princeton Univ., NJ (United States); Cava, R. J. [Princeton Univ., NJ (United States); Fernandes, R. M. [Univ., of Minnesota, Minneapolis, MN (United States); Millis, A. J. [Columbia Univ., New York, NY (United States); Osgood, Jr., R. M. [Columbia Univ., New York, NY (United States); Princeton Univ., Princeton, NJ (United States); Pasupathy, A. N. [Columbia Univ., New York, NY (United States)

    2015-01-01

    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 and the 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.

  15. 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

  16. Effects of charge inhomogeneities on elementary excitations in La2-xSrxCuO?

    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-xSrxCuO? 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

  17. 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 andmore »the 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

  18. 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. [Columbia Univ., New York, NY (United States); Valla, T. [Brookhaven National Lab. (BNL), Upton, NY (United States); Rosenthal, E. P. [Columbia Univ., New York, NY (United States); Andrade, E. F. [Columbia Univ., New York, NY (United States); Jin, W. [Columbia Univ., New York, NY (United States); Yeh, P. C. [Columbia Univ., New York, NY (United States); Zaki, N. [Columbia Univ., New York, NY (United States); Jia, S. [Princeton Univ., NJ (United States); Cava, R. J. [Princeton Univ., NJ (United States); Fernandes, R. M. [Univ., of Minnesota, Minneapolis, MN (United States); Millis, A. J. [Columbia Univ., New York, NY (United States); Osgood, Jr., R. M. [Columbia Univ., New York, NY (United States); Princeton Univ., Princeton, NJ (United States); Pasupathy, A. N. [Columbia Univ., New York, NY (United States)

    2015-01-01

    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 and the 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.

  19. 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-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?. 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-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

  20. 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.

  1. 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}.

  2. Absolute Measurement Of Laminar Shear Rate Using Photon Correlation Spectroscopy

    E-Print Network [OSTI]

    Elliot Jenner; Brian D'Urso

    2015-05-11

    An absolute measurement of the components of the shear rate tensor $\\mathcal{S}$ in a fluid can be found by measuring the photon correlation function of light scattered from particles in the fluid. Previous methods of measuring $\\mathcal{S}$ involve reading the velocity at various points and extrapolating the shear, which can be time consuming and is limited in its ability to examine small spatial scale or short time events. Previous work in Photon Correlation Spectroscopy has involved only approximate solutions, requiring free parameters to be scaled by a known case, or different cases, such as 2-D flows, but here we present a treatment that provides quantitative results directly and without calibration for full 3-D flow. We demonstrate this treatment experimentally with a cone and plate rheometer.

  3. 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.

  4. Temperature dependence of bulk viscosity in water using acoustic spectroscopy

    E-Print Network [OSTI]

    M. J. Holmes; N. G. Parker; M. J. W. Povey

    2010-02-16

    Despite its fundamental role in the dynamics of compressible fluids, bulk viscosity has received little experimental attention and there remains a paucity of measured data. Acoustic spectroscopy provides a robust and accurate approach to measuring this parameter. Working from the Navier-Stokes model of a compressible fluid one can show that the bulk viscosity makes a significant and measurable contribution to the frequency-squared acoustic attenuation. Here we employ this methodology to determine the bulk viscosity of Millipore water over a temperature range of 7 to 50 degrees Celsius. The measured attenuation spectra are consistent with the theoretical predictions, while the bulk viscosity of water is found to be approximately three times larger than its shear counterpart, reinforcing its significance in acoustic propagation. Moreover, our results demonstrate that this technique can be readily and generally applied to fluids to accurately determine their temperature dependent bulk viscosities.

  5. 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.

  6. Optical gradient force nano-imaging and -spectroscopy

    E-Print Network [OSTI]

    Yang, Honghua U

    2015-01-01

    Nanoscale forces play an important role in different scanning probe microscopies, most notably atomic force microscopy (AFM). In contrast, in scanning near-field optical microscopy (SNOM) a light-induced coupled local optical polarization between tip and sample is typically detected by scattering to the far field. Measurements of the optical gradient force associated with that optical near-field excitation would offer a novel optical scanning probe modality. Here we provide a generalized theory of optical gradient force nano-imaging and -spectroscopy. We quantify magnitude and distance dependence of the optical gradient force and its spectral response. We show that the optical gradient force is dispersive for single particle electronic and vibrational resonances, distinct from recent claims of its experimental observation. In contrast, the force can be absorptive for collective resonances. We provide a guidance for its measurements and distinction from competing processes such as thermal expansion.

  7. 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.

  8. 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 ?M 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 ?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.« less

  9. 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.

  10. ANTIHYDROGEN PRODUCTION AND PRECISION SPECTROSCOPY WITH ATHENA/AD-1

    SciTech Connect (OSTI)

    M. HOLZSCHEITER; C. AMSLER; ET AL

    2000-11-01

    CPT invariance is a fundamental property of quantum field theories in flat space-time. Principal consequences include the predictions that particles and their antiparticles have equal masses and lifetimes, and equal and opposite electric charges and magnetic moments. It also follows that the fine structure, hyperfine structure, and Lamb shifts of matter and antimatter bound systems should be identical. It is proposed to generate new stringent tests of CPT using precision spectroscopy on antihydrogen atoms. An experiment to produce antihydrogen at rest has been approved for running at the Antiproton Decelerator (AD) at CERN. We describe the fundamental features of this experiment and the experimental approach to the first phase of the program, the formation and identification of low energy antihydrogen.

  11. 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.

  12. Quasinormal mode theory and modelling of electron energy loss spectroscopy

    E-Print Network [OSTI]

    Ge, Rong-Chun

    2015-01-01

    Modelling electron energy loss spectroscopy (EELS) presents a major challenge in computational electrodynamics, requiring the full photon Green function as a function of two space points and frequency. In this work, we present an intuitive and computationally simple method for computing EELS maps using a quasinormal mode (QNM) expansion technique. By separating the contribution of the QNM and the bulk material, we give closed-form analytical formulas for the plasmonic QNM contribution to EELS images. We exemplify our technique for a split ring resonator, a gold nanorod, and a nanorod dimer structure. The method is accurate, intuitive, and gives orders of magnitude improvements over direct dipole simulations that numerically solve the full 3D Maxwell equations.

  13. 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.

  14. High-resolution X-ray spectroscopy of Theta Car

    E-Print Network [OSTI]

    Yael Naze; Gregor Rauw

    2008-08-25

    Context : The peculiar hot star Theta Car in the open cluster IC2602 is a blue straggler as well as a single-line binary of short period (2.2d). Aims : Its high-energy properties are not well known, though X-rays can provide useful constraints on the energetic processes at work in binaries as well as in peculiar, single objects. Methods : We present the analysis of a 50ks exposure taken with the XMM-Newton observatory. It provides medium as well as high-resolution spectroscopy. Results : Our high-resolution spectroscopy analysis reveals a very soft spectrum with multiple temperature components (1--6MK) and an X-ray flux slightly below the `canonical' value (log[L_X(0.1-10.)/L_{BOL}] ~ -7). The X-ray lines appear surprisingly narrow and unshifted, reminiscent of those of beta Cru and tau Sco. Their relative intensities confirm the anomalous abundances detected in the optical domain (C strongly depleted, N strongly enriched, O slightly depleted). In addition, the X-ray data favor a slight depletion in neon and iron, but they are less conclusive for the magnesium abundance (solar-like?). While no significant changes occur during the XMM-Newton observation, variability in the X-ray domain is detected on the long-term range. The formation radius of the X-ray emission is loosely constrained to <5 R_sol, which allows for a range of models (wind-shock, corona, magnetic confinement,...) though not all of them can be reconciled with the softness of the spectrum and the narrowness of the lines.

  15. 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.

  16. COORDINATED SPECTROSCOPIC AND PETROLOGIC INVESTIGATION OF LAP 04840: FIRST RESULTS OF INFRARED, THERMAL AND RAMAN SPECTROSCOPY. R. Klima1

    E-Print Network [OSTI]

    Hiroi, Takahiro

    of studies have shown that a joint ap- proach integrating petrography, Mössbauer, infrared spectroscopy and petrography [5] Mössbauer spectroscopy [6], and metamorphic condi- tions [7] are also described in this volume

  17. Distribution of Carbon Impurity Sources Between Low and High Field Side Measured via Zeeman-Spectroscopy in JET

    E-Print Network [OSTI]

    Distribution of Carbon Impurity Sources Between Low and High Field Side Measured via Zeeman-Spectroscopy in JET

  18. Neutron Emission Spectroscopy of Fuel Ion Rotation and Fusion Power Components Demonstrated in the Trace Tritium Experiments at JET

    E-Print Network [OSTI]

    Neutron Emission Spectroscopy of Fuel Ion Rotation and Fusion Power Components Demonstrated in the Trace Tritium Experiments at JET

  19. AF3KI.4.pdf ACP/IPOC 2013 OSA 2013 Broadband photon time of flight spectroscopy: advanced

    E-Print Network [OSTI]

    .6190) Spectrometers; (290.7050) Turbid media; (290.4210) Multiple scattering; (00.6250) Spectroscopy, condensed matter

  20. High-Energy Fuel Ion Diagnostics on ITER Derived from Neutron Emission Spectroscopy Measurements on JET DT Plasmas

    E-Print Network [OSTI]

    High-Energy Fuel Ion Diagnostics on ITER Derived from Neutron Emission Spectroscopy Measurements on JET DT Plasmas

  1. Investigations on optoelectronic transition mechanisms of silicon nanoporous pillar array by using surface photovoltage spectroscopy and photoluminescence spectroscopy

    SciTech Connect (OSTI)

    Hu, Zhen-Gang, E-mail: huzhengang@zzu.edu.cn; Tian, Yong-Tao; Li, Xin-Jian [Department of Physics and Laboratory of Material Physics, Zhengzhou University, Zhengzhou 450001 (China)

    2014-03-28

    We report the electronic transition mechanisms for hydrothermally prepared silicon nanoporous pillar array (Si-NPA), investigated by surface photovoltage (SPV) spectroscopy and photoluminescence (PL) spectroscopy. By comparing the SPV spectra of single crystal silicon (sc-Si) with that of Si-NPA, the silicon nano-crystallites (nc-Si)/SiO{sub x} nanostructure in the Si-NPA could produce SPV in the wavelength range of 300–580?nm. And 580?nm (?2.14?eV) was considered as the absorption edge of the nc-Si/SiO{sub x} nanostructure. After the sample was annealed and oxidized in air at different temperatures, both the SPV in the wavelength range of 300–580?nm and the PL emission band around 690?nm from the nc-Si/SiO{sub x} nanostructure weakened and disappeared as the annealing temperature increased from 100 to 500?°C. But both the red-infrared PL band (>710?nm) and the violet-blue PL band were enhanced by increasing the annealing temperature. After 2 years of natural oxidation in air, the SPV features for sc-Si disappeared completely, and the SPV characteristics of the nc-Si/SiO{sub x} nanostructure could be clearly observed. After analysis, the Si–O structure related localized states at the nc-Si/SiO{sub x} interface dominated the electronic transitions during the red PL emission and the SPV for the nc-Si/SiO{sub x} nanostructure in Si-NPA, the red–infrared PL was due to the Si=O structure related electronic transitions, and the violet-blue PL emission could attribute to the oxygen-related defect related recombination of the photo induced carriers.

  2. Widespread spin polarizationeffects in photoemission from topological insulators

    E-Print Network [OSTI]

    Jozwiak, C.

    2012-01-01

    potential application in spintronics de- vices. This unusualfor room-temperature spintronics applications. In summary,

  3. 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.

  4. High-resolution inverse Raman and resonant-wave-mixing spectroscopy

    SciTech Connect (OSTI)

    Rahn, L.A. [Sandia National Laboratories, Livermore, CA (United States)

    1993-12-01

    These research activities consist of high-resolution inverse Raman spectroscopy (IRS) and resonant wave-mixing spectroscopy to support the development of nonlinear-optical techniques for temperature and concentration measurements in combustion research. Objectives of this work include development of spectral models of important molecular species needed to perform coherent anti-Stokes Raman spectroscopy (CARS) measurements and the investigation of new nonlinear-optical processes as potential diagnostic techniques. Some of the techniques being investigated include frequency-degenerate and nearly frequency-degenerate resonant four-wave-mixing (DFWM and NDFWM), and resonant multi-wave mixing (RMWM).

  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. 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.

  7. 2003 Electronic Spectroscopy and Dynamics - July 6-11, 2003

    SciTech Connect (OSTI)

    Elliot Bernstein

    2004-09-10

    The Gordon Research Conference (GRC) on 2003 Electronic Spectroscopy and Dynamics - July 6-11, 2003 was held at Bates College, Lewiston, Maine, July 6-11, 2003. The Conference was well-attended with 103 participants (attendees list attached). The attendees represented the spectrum of endeavor in this field coming from academia, industry, and government laboratories, both U.S. and foreign scientists, senior researchers, young investigators, and students. In designing the formal speakers program, emphasis was placed on current unpublished research and discussion of the future target areas in this field. There was a conscious effort to stimulate lively discussion about the key issues in the field today. Time for formal presentations was limited in the interest of group discussions. In order that more scientists could communicate their most recent results, poster presentation time was scheduled. Attached is a copy of the formal schedule and speaker program and the poster program. In addition to these formal interactions, ''free time'' was scheduled to allow informal discussions. Such discussions are fostering new collaborations and joint efforts in the field.

  8. Infrared Spectroscopy of U Equulei's Warm Circumstellar Gas

    E-Print Network [OSTI]

    T. R. Geballe; C. Barnbaum; Keith S. Noll; M. Morris

    2005-03-18

    Medium and high resolution spectroscopy of U Equulei from 1 to 4 microns during 1997-2003 has revealed information about its unusual circumstellar envelope, observed previously at optical and radio wavelengths. Strong absorption bands of H2O and of CO dominate the 1-4um spectrum. The gas has a mean temperature of 600 K and 12C/13C =< 10. The CO 2-0 line profiles and velocities imply no net ejection or infall and indicate either rapid radial gas motions being seen along a narrow continuum beam, or absorption by orbiting gas that is nearly coincident with a highly extended continuum source. The gas could be located in a disk-like structure. The observed high column densities of warm CO and H2 normally would be associated with sufficient dust to completely obscure the star at optical wavelengths. The observations thus indicate either a highly abnormal gas-to-dust ratio, consistent with the earlier optical observation of abundant refractory metal oxides in the circumstellar gas, or peculiar geometry and/or illumination.

  9. Open quantum system approach to single-molecule spectroscopy

    E-Print Network [OSTI]

    Adrian A. Budini

    2009-02-23

    In this paper, single-molecule spectroscopy experiments based on continuous laser excitation are characterized through an open quantum system approach. The evolution of the fluorophore system follows from an effective Hamiltonian microscopic dynamic where its characteristic parameters, i.e., its electric dipole, transition frequency, and Rabi frequency, as well as the quantization of the background electromagnetic field and their mutual interaction, are defined in an extended Hilbert space associated to the different configurational states of the local nano-environment. After tracing out the electromagnetic field and the configurational states, the fluorophore density matrix is written in terms of a Lindblad rate equation. Observables associated to the scattered laser field, like optical spectrum, intensity-intensity correlation, and photon-counting statistics, are obtained from a quantum-electrodynamic calculation also based on the effective microscopic dynamic. In contrast with stochastic models, this approach allows to describe in a unified way both the full quantum nature of the scattered laser field as well as the classical nature of the environment fluctuations. By analyzing different processes such as spectral diffusion, lifetime fluctuations, and light assisted processes, we exemplify the power of the present approach.

  10. 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

  11. 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.

  12. 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.

  13. Physics beyond the Standard Model from hydrogen spectroscopy

    E-Print Network [OSTI]

    Ubachs, Wim; Eikema, Kjeld S E; Salumbides, Edcel J

    2015-01-01

    Spectroscopy of hydrogen can be used for a search into physics beyond the Standard Model. Differences between the absorption spectra of H$_2$ as observed at high redshift and those measured in the laboratory can be interpreted in terms of possible variations of the proton-electron mass ratio. Investigation of some ten of such absorbers in the redshift range $z= 2.0-4.2$ yields a constraint of $|\\Delta\\mu/\\mu|< 5 \\times 10^{-6}$ at 3$\\sigma$. Observation of H$_2$ from the photospheres of white dwarf stars inside our Galaxy delivers a constraint of similar magnitude on a dependence of $\\mu$ on a gravitational potential $10^4$ times as strong as on the Earth's surface. Laser-based precision measurements of dissociation energies, vibrational splittings and rotational level energies in H$_2$ molecules and their deuterated isotopomers HD and D$_2$ produce values for the rovibrational binding energies fully consistent with quantum ab initio calculations including relativistic and quantum electrodynamical (QED) ef...

  14. 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.

  15. 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.

  16. Active plasma resonance spectroscopy: A functional analytic description

    E-Print Network [OSTI]

    Lapke, Martin; Mussenbrock, Thomas; Brinkmann, Ralf Peter

    2012-01-01

    The term "Active Plasma Resonance Spectroscopy" refers to a class of diagnostic methods which employ the ability of plasmas to resonate on or near the plasma frequency. The basic idea dates back to the early days of discharge physics: An signal in the GHz range is coupled to the plasma via an electrical probe; the spectral response is recorded, and then evaluated with a mathematical model to obtain information on the electron density and other plasma parameters. In recent years, the concept has found renewed interest as a basis of industry compatible plasma diagnostics. This paper analyzes the diagnostics technique in terms of a general description based on functional analytic (or Hilbert Space) methods which hold for arbitrary probe geometries. It is shown that the response function of the plasma-probe system can be expressed as a matrix element of the resolvent of an appropriately defined dynamical operator. A specialization of the formalism for a symmetric probe desing is given, as well as an interpreation...

  17. HESS Observations and VLT Spectroscopy of PG 1553+113

    E-Print Network [OSTI]

    Aharonian, F; Barresde Almeida, U; Bazer-Bachi, A R; Behera, B; Beilicke, M; Benbow, W; Bernlöhr, K; Boisson, C; Bolz, O; Borrel, V; Braun, I; Brion, E; Brown, A M; Buhler, R; Bulik, T; Büsching, I; Boutelier, T; Carrigan, S; Chadwick, P M; Chounet, L M; Clapson, A C; Coignet, G; Cornils, R; Costamante, L; Dalton, M; Degrange, B; Dickinson, H J; Djannati-Ata, A; Domainko, W; O'Connor-Drury, L; Dubois, F; Dubus, G; Dyks, J; Egberts, K; Emmanoulopoulos, D; Espigat, P; Farnier, C; Feinstein, F; Fiasson, A; Frster, A; Fontaine, G; Funk, Seb; Fuling, M; Gallant, Y A; Giebels, B; Glicenstein, J F; Glück, B; Goret, P; Hadjichristidis, C; Hauser, D; Hauser, M; Heinzelmann, G; Henri, G; Hermann, G; Hinton, J A; Hoffmann, A; Hofmann, W; Holleran, M; Hoppe, S; Horns, D; Jacholkowska, A; De Jager, O C; Jung, I; Katarzynski, K; Kendziorra, E; Kerschhaggl, M; Khlifi, B; Keogh, D; Komin, Nu; Kosack, K; Lamanna, G; Latham, I J; Lemiere, A; Lemoine-Goumard, M; Lenain, J P; Lohse, T; Martin, J M; Martineau-Huynh, O; Marcowith, A; Masterson, C; Maurin, D; Maurin, G; McComb, T J L; Moderski, R; Moulin, E; De Naurois, Mathieu; Nedbal, D; Nolan, S J; Ohm, S; Olive, J P; de Ona Wilhelmi, E; Orford, K J; Osborne, J L; Ostrowski, M; Panter, M; Pedaletti, G; Pelletier, G; Petrucci, P O; Pita, S; Pühlhofer, G; Punch, M; Ranchon, S; Raubenheimer, B C; Raue, M; Rayner, S M; Renaud, M; Ripken, J; Rob, L; Rolland, L; Rosier-Lees, S; Rowell, G; Rudak, B; Ruppel, J; Sahakian, V V; Santangelo, A; Schlickeiser, R; Schock, F; Schroder, R; Schwanke, U; Schwarzburg, S; Schwemmer, S; Sol, H; Spangler, D; Stawarz, L; Steenkamp, R; Stegmann, C; Superina, G; Tam, A Shalchi P H; Tavernet, J P; Terrier, R; Van Eldik, C; Vasileiadis, G; Venter, C; Vialle, J P; Vincent, P; Vivier, M; Vlk, H J; Volpe, F; Wagner, S J; Ward, M; Zdziarski, A A; Zech, A; Ablikim, M

    2007-01-01

    AIMS: The properties of the very high energy (VHE; E>100 GeV) gamma-ray emission from the high-frequency peaked BL Lac PG 1553+113 are investigated. An attempt is made to measure the currently unknown redshift of this object. METHODS: VHE Observations of PG 1553+113 were made with the High Energy Stereoscopic System (HESS) in 2005 and 2006. H+K (1.45-2.45 micron) spectroscopy of PG 1553+113 was performed in March 2006 with SINFONI, an integral field spectrometer of the ESO Very Large Telescope (VLT) in Chile. RESULTS: A VHE signal, ~10 standard deviations, is detected by HESS during the 2 years of observations (24.8 hours live time). The integral flux above 300 GeV is (4.6 +- 0.6{stat} +- 0.9{syst}) x 10^{-12} cm^{-2} s^{-1}, corresponding to ~3.4% of the flux from the Crab Nebula above the same threshold. The time-averaged energy spectrum is measured from 225 GeV to ~1.3 TeV, and is characterized by a very soft power law (photon index of Gamma = 4.5 +- 0.3{stat} +- 0.1{syst}). No evidence for any flux or spe...

  18. Photoelectron spectroscopy of wet and gaseous samples through graphene membranes

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

    Kraus, Jürgen; Reichelt, Robert; Günther, 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 liquid–gas, solid–liquid and solid–gas 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 molecularmore »impermeable 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

  19. Enhancing the analytical performance of laser-induced breakdown spectroscopy

    SciTech Connect (OSTI)

    Cremers, D.A.; Chinni, R.C.; Pichahchy, A.E.; Thornquist, H.K.

    1998-12-31

    This is the final report of a one-year, Laboratory Directed Research and Development (LDRD) project at Los Alamos National Laboratory (LANL). The objective of this work is to enhance the analytical capabilities of laser-induced breakdown spectroscopy (LIBS). LIBS is a method of elemental analysis in which powerful laser pulses are focused on a sample to form a microplasma. LIBS is perhaps the most versatile elemental analysis method, applicable to a variety of different real-world analysis problems. Therefore, it is important to enhance the capabilities of the method as much as possible. Accomplishments include: (1) demonstration of signal enhancements of 5--30 times from soils and metals using a double pulse method; (2) development of a model of the observed enhancement obtained using double pulses; (3) demonstration that the analytical performance achievable using low laser-pulse energies (10 and 25 mJ) can match that achievable using an energy of 100 mJ; and (4) demonstration that time-gated detection is not necessary with LIBS.

  20. Phosphorus K-edge XANES Spectroscopy of Mineral Standards

    SciTech Connect (OSTI)

    E Ingall; J Brandes; J Diaz; M de Jonge; D Paterson; I McNulty; C Elliott; P Northrup

    2011-12-31

    Phosphorus K-edge X-ray absorption near-edge structure (XANES) spectroscopy was performed on phosphate mineral specimens including (a) twelve specimens from the apatite group covering a range of compositional variation and crystallinity; (b) six non-apatite calcium-rich phosphate minerals; (c) 15 aluminium-rich phosphate minerals; (d) ten phosphate minerals rich in either reduced iron or manganese; (e) four phosphate minerals rich in either oxidized iron or manganese; (f) eight phosphate minerals rich in either magnesium, copper, lead, zinc or rare-earth elements; and (g) four uranium phosphate minerals. The identity of all minerals examined in this study was independently confirmed using X-ray powder diffraction. Minerals were distinguished using XANES spectra with a combination of pre-edge features, edge position, peak shapes and post-edge features. Shared spectral features were observed in minerals with compositions dominated by the same specific cation. Analyses of apatite-group minerals indicate that XANES spectral patterns are not strongly affected by variations in composition and crystallinity typical of natural mineral specimens.

  1. 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).

  2. Auger electron spectroscopy and x-ray photoelectron spectroscopy of the biocorrosion of copper by Gum Arabic, BCS and Pseudomonas atlantica exopolymer

    SciTech Connect (OSTI)

    Jolley, J.G.; Geesey, G.G.; Hankins, M.R.; Wright, R.B.; Wichlacz, P.L.

    1987-01-01

    Thin films (3.4 nm) of copper on germanium substrates were exposed to 10% Gum Arabic aqueous solution, 1% BCS (aqueous and simulated sea water solutions) and 0.5% Pseudomonas atlantica exopolymer (aqueous and simulated sea water solutions). Pre- and post-exposure characterization were done by Auger electron spectroscopy and x-ray photoelectron spectroscopy. Ancillary graphite furnace atomic absorption spectroscopy was used to monitor the removal process of the copper thin film from the germanium substrate. Results indicate that the copper was oxidized by the Gum Arabic and BCS, and some was removed from the Cu/Ge interface by all three polymers and incorporated into the polymer matrix. Thus biocorrosion of copper was exhibited by the Gum Arabic, BCS and Pseudomonas atlantica exopolymer. 14 refs., 4 figs., 3 tabs.

  3. Raman Spectroscopy Provides a Powerful Diagnostic Tool for Accurate Determination of Albumin Glycation

    E-Print Network [OSTI]

    Dingari, Narahara Chari

    We present the first demonstration of glycated albumin detection and quantification using Raman spectroscopy without the addition of reagents. Glycated albumin is an important marker for monitoring the long-term glycemic ...

  4. DEEP LEVEL TRANSIENT SPECTROSCOPY OF HIGH-PURITY GERMANIUM DIODES/DETECTORS

    E-Print Network [OSTI]

    Haller, E.E.

    2011-01-01

    1978 LBL,-3140"'/ c-. cr DEEP LEVEL TRANSIENT SPECTROSCOPY.are changing the charge state of deep traps. A minority trapenergy and concentration of deep traps in high-purity Ge, it

  5. 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.

  6. Fourier Transform Raman Spectroscopy of Photoactive Proteins with Near-Infrared Excitation

    E-Print Network [OSTI]

    Johnson, Carey K.; Rubinovitz, Ronald

    1990-07-01

    ) and bacteriopheophytin, bacteriochlorophyll, and carotenoids (in reaction centers). The relative intensities of retinylidene modes in the spectrum for nonresonant FT Raman spectroscopy of bacteriorhodopsin are nearly identical to those observed in the resonance Raman...

  7. Vacuum ultraviolet mass-analyzed threshold ionization spectroscopy of methylcyclohexane in the supersonic jet

    E-Print Network [OSTI]

    Kim, Sang Kyu

    Vacuum ultraviolet mass-analyzed threshold ionization spectroscopy of methylcyclohexane t Vacuum ultraviolet (VUV) mass-analyzed threshold ionization (MATI) spectrum of supersonically cooled the vacuum ultraviolet (VUV) laser source is particu- larly useful for molecular systems with no stable

  8. The use of chirped pulse millimeter-wave spectroscopy in chemical dynamics and kinetics

    E-Print Network [OSTI]

    Shaver, Rachel Glyn

    2013-01-01

    .Chirped-pulse millimeter wave (CPmmW) spectroscopy is a revolutionary technique that has taken advantage of advances in electronics to give high signal to noise broadband rotational spectra in a very short period of time ...

  9. Study of granular temperature in dense fluidized beds by diffusing wave spectroscopy 

    E-Print Network [OSTI]

    Zivkovic, Vladimir

    2009-01-01

    Diffusing wave spectroscopy (DWS), a non-intrusive multiple scattering technique, can be used to study the fundamentals of particle motion in dynamic dense granular media and measure the mean of the square of the particle ...

  10. Interfacial Water Organization and Ion Distributions Investigated with Vibrational Sum Frequency Spectroscopy: Answering Fundamental Questions for

    E-Print Network [OSTI]

    Spectroscopy: Answering Fundamental Questions for Environmental Chemistry DISSERTATION Presented in Partial sum frequency generation (VSFG) and heterodyne-detected vibrational sum frequency generation (HD a series of systematic studies. Results indicate that the ion-induced interfacial electric field

  11. Developments in time-resolved ultrafast imaging and spectroscopy at terahertz frequencies

    E-Print Network [OSTI]

    Teo, Stephanie M

    2014-01-01

    Prior to the advent of high energy pulsed femtosecond lasers, the field of terahertz (THz) spectroscopy was stagnated by the lack of both high power THz sources and sensitive THz detectors. Over the past few years, it has ...

  12. Coherent two-exciton dynamics measured using two-quantum rephasing two-dimensional electronic spectroscopy

    E-Print Network [OSTI]

    Turner, Daniel B.

    We use fifth-order two-dimensional electronic spectroscopy to measure coherent four-particle dynamics in a semiconductor nanostructure. By using optical polarization control in two-quantum measurements enabled by the COLBERT ...

  13. A tale of coupled vibrations in solution told by coherent two-dimensional infrared spectroscopy

    E-Print Network [OSTI]

    Khalil, Munira, 1975-

    2004-01-01

    Coherent two-dimensional infrared (2D IR) spectroscopy is used as a tool for investigating the molecular structure and dynamics of coupled vibrations in solution on a picosecond timescale. The strongly coupled asymmetric ...

  14. X-ray imaging crystal spectroscopy for use in plasma transport research

    E-Print Network [OSTI]

    Bitter, M.

    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 ...

  15. The Design of Novel Microwave-Heated Reaction Cells for Infrared Spectroscopy 

    E-Print Network [OSTI]

    Silverwood, Ian P

    Two novel microreactor cells for the investigation of catalysts by in-situ infrared spectroscopy under microwave and conventional heating are presented. A transmission infrared microreactor cell is demonstrated which ...

  16. Single-fiber-laser-based wavelength tunable excitation for coherent Raman spectroscopy

    E-Print Network [OSTI]

    Su, Jue; Xie, Ruxin; Johnson, Carey K.; Hui, Rongqing

    2013-06-01

    We demonstrate coherent Raman spectroscopy (CRS) using a tunable excitation source based on a single femtosecond fiber laser. The frequency difference between the pump and the Stokes pulses was generated by soliton self-frequency shifting in a...

  17. Solar Energy Materials & Solar Cells 71 (2002) 511522 In situ Raman spectroscopy of the

    E-Print Network [OSTI]

    Nabben, Reinhard

    2002-01-01

    Solar Energy Materials & Solar Cells 71 (2002) 511­522 In situ Raman spectroscopy. In this situation, a low energy excitation (e.g. visible light) is needed to excite an electron to a neighboring

  18. High Frequency Sampling of TTL Pulses on a Raspberry Pi for Diffuse Correlation Spectroscopy Applications

    E-Print Network [OSTI]

    Tivnan, Matthew

    Diffuse Correlation Spectroscopy (DCS) is a well-established optical technique that has been used for non-invasive measurement of blood flow in tissues. Instrumentation for DCS includes a correlation device that computes ...

  19. Single-shot spectroscopy of solid-state photoinduced dynamics far from equilibrium

    E-Print Network [OSTI]

    Wolfson, Johanna Wendlandt

    2013-01-01

    Ultrafast single-shot spectroscopy was developed and improved as a method to observe photoinduced dynamics far from equilibrium. The method was then employed to illuminate material dynamics in platinum-halide quasi-one-dimensional ...

  20. UV Spectroscopy of Type Ia Supernovae at Low- and High-Redshift

    E-Print Network [OSTI]

    Nugent, Peter

    2005-01-01

    Spectroscopy of Type Ia Supernovae at Low- and High-RedshiftUV properties of Type Ia Supernovae. The low-redshift studyULDA Access Guide No. 6: Supernovae, The Netherlands: ESA

  1. Radon spectroscopy of packet delay Andre Broido, Ryan King, Evi Nemeth, kc claffy

    E-Print Network [OSTI]

    California at San Diego, University of

    Radon spectroscopy of packet delay Andre Broido, Ryan King, Evi Nemeth, kc claffy CAIDA, SDSC techniques, specifically the Radon transform previously applied in geophysics [6] and computer tomography [7

  2. Radon spectroscopy of packet delay Andre Broido, Ryan King, Evi Nemeth, kc cla#y

    E-Print Network [OSTI]

    California at San Diego, University of

    Radon spectroscopy of packet delay Andre Broido, Ryan King, Evi Nemeth, kc cla#y CAIDA, SDSC techniques, specifically the Radon transform previously applied in geophysics [6] and computer tomography [7

  3. Spectroscopy and external control of optical dynamics in single semiconductor nanocrystals

    E-Print Network [OSTI]

    Shimizu, Kentaro, 1975-

    2002-01-01

    Single molecule spectroscopy has progressed substantially in the past ten years and the accompanying progress in the optical study of single semiconductor nanocrystals has opened a new dimension in our understanding of the ...

  4. High resolution laser spectroscopy of cesium and rubidium molecules with optically induced coherence 

    E-Print Network [OSTI]

    Chen, Hui

    2006-10-30

    This work is devoted to the study of the quantum coherent effects in diatomic molecular systems by using high resolution laser spectroscopy. In particular, we have studied the rubidium diatomic molecular gaseous medium's ...

  5. Characterization of a synthetic peroxodiiron(III) protein model complex by nuclear resonance vibrational spectroscopy

    E-Print Network [OSTI]

    Do, Loi Hung

    The vibrational spectrum of an ?[superscript 1],?[superscript 1]-1,2-peroxodiiron(III) complex was measured by nuclear resonance vibrational spectroscopy and fit using an empirical force field analysis. Isotopic 18O2 ...

  6. Higher Order Amyloid Fibril Structure by MAS NMR and DNP Spectroscopy

    E-Print Network [OSTI]

    Debelouchina, Galia T.

    Protein magic angle spinning (MAS) NMR spectroscopy has generated structural models of several amyloid fibril systems, thus providing valuable information regarding the forces and interactions that confer the extraordinary ...

  7. Quantum chemistry for spectroscopy : a tale of three spins (S = 0, 1/2, and 1)

    E-Print Network [OSTI]

    Wong, Bryan Matthew, 1979-

    2007-01-01

    Three special topics in the field of molecular spectroscopy are investigated using a variety of computational techniques. First, large-amplitude vibrational motions on ground-state singlet (S0) potential energy surfaces ...

  8. 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 (sub-ns) time resolution Citation Details In-Document Search Title: A new spectrometer...

  9. Methods for Increasing Sensitivity and Throughput of Solid-State NMR Spectroscopy of Pharmaceutical Solids

    E-Print Network [OSTI]

    Schieber, Loren

    2010-01-22

    Solid-state nuclear magnetic resonance (SSNMR) spectroscopy has been demonstrated to be a powerful technique for investigating solid dosage formulations. SSNMR has the ability to determine physical form, molecular structure, ...

  10. Demonstration of Ballistic Electron Emission Microscopy / Spectroscopy on the Au/Si (001) system 

    E-Print Network [OSTI]

    Drummond, Mary Alyssa

    1997-01-01

    gold surface. The barrier heights of the diodes were extracted from the ballistic electron emission spectroscopy with the use of a simple one dimensional BEEM current model. Comparison between the barrier heights obtained with BEEM and conventional I...

  11. Direct observation of Rydberg-Rydberg transitions via CPmmW spectroscopy

    E-Print Network [OSTI]

    Zhou, Yan, Ph. D. Massachusetts Institute of Technology

    2014-01-01

    Rydberg-Rydberg transitions of BaF molecules have been directly observed in our lab. The key to the experimental success is our ability to combine two powerful and new technologies, Chirped-Pulse millimeter-Wave spectroscopy ...

  12. Nighttime Measurements of Dinitrogen Pentoxide and the Nitrate Radical via Cavity Ring-Down Spectroscopy 

    E-Print Network [OSTI]

    Perkins, Katie C.

    2010-10-12

    technique, known as cavity ring-down spectroscopy, will be introduced for simultaneously measuring the nitrate radical and dinitrogen pentoxide. The cavity ring-down spectrometer was initially designed and constructed based on the experiments by Steven Brown...

  13. Rf coil design for multi-frequency magnetic resonance imaging & spectroscopy 

    E-Print Network [OSTI]

    Dabirzadeh, Arash

    2009-05-15

    Magnetic Resonance Spectroscopy is known as a valuable diagnostic tool for physicians as well as a research tool for biochemists. In addition to hydrogen (which is the most abundant atom with nuclear magnetic resonance capability), other species...

  14. Carrier envelope phase stabilization of a femtosecond laser and iodine spectroscopy 

    E-Print Network [OSTI]

    Zhu, Feng

    2006-10-30

    saturation spectroscopy was set up to provide a precise frequency reference to which a CW dye laser can be locked on. The near future goal is to accurately measure this frequency stabilized dye laser with the optical frequency synthesizer....

  15. Study of the Corrosion Resistance of Benchmark Coatings Using Electrochemical Impedance Spectroscopy 

    E-Print Network [OSTI]

    Ghannam, Safwan

    2015-04-28

    The corrosion resistance of polymer-coated carbon steel exposed to corrosive environment of 3.5% NaCl solution (weight fraction) at ambient conditions was evaluated using electrochemical impedance spectroscopy (EIS) technique. The analysis...

  16. Automation of the Laguerre Expansion Technique for Analysis of Time-resolved Fluorescence Spectroscopy Data 

    E-Print Network [OSTI]

    Dabir, Aditi Sandeep

    2010-07-14

    Time-resolved fluorescence spectroscopy (TRFS) is a powerful analytical tool for quantifying the biochemical composition of organic and inorganic materials. The potentials of TRFS as nondestructive clinical tool for tissue diagnosis have been...

  17. Development of a Time Resolved Fluorescence Spectroscopy System for Near Real-Time Clinical Diagnostic Applications 

    E-Print Network [OSTI]

    Trivedi, Chintan A.

    2010-07-14

    The design and development of a versatile time resolved fluorescence spectroscopy (TRFS) system capable of near real time data acquisition and processing for potential clinical diagnostic applications is reported. The TRFS apparatus is portable...

  18. Chemisorption of Aromatic Compounds on Well-Defined Palladium Surfaces: Studies by Electron Spectroscopy and Electrochemistry 

    E-Print Network [OSTI]

    Li, Ding

    2010-10-12

    The chemisorption of aromatic compounds, derivatized with different functional groups, on well-defined Pd(111) surfaces was studied by a combination of Auger electron spectroscopy (AES), low energy electron diffraction (LEED), high resolution...

  19. A Broadband Miniaturized Microwave Dielectric Spectroscopy System Based on Impedance Sensing 

    E-Print Network [OSTI]

    Kabiri, Saman 1988-

    2013-01-07

    The main purpose of this thesis is to propose a broadband miniaturized spectroscopy system to detect dielectric constant and loss tangent of lossy organic materials at RF/Microwave frequencies. Complex permittivities of lossy liquids are measured...

  20. Design and Simulation of Coils for High Field Magnetic Resonance Imaging and Spectroscopy 

    E-Print Network [OSTI]

    Rispoli, Joseph V

    2015-06-05

    The growing availability of high-field magnetic resonance (MR) scanners has reignited interest in the in vivo investigation of metabolics in the body. In particular, multinuclear MR spectroscopy (MRS) data reveal physiological details inaccessible...

  1. Atom microscopy via two-photon spontaneous emission spectroscopy RID A-5077-2009 

    E-Print Network [OSTI]

    Qamar, Sajid; Evers, Joerg; Zubairy, M. Suhail

    2009-01-01

    We study subwavelength position measurement via spontaneous emission spectroscopy with two photons. Our model systems are a single Lambda-type three-level atom, in which a dual interaction generates two independent photons, and an M-type five...

  2. Development of a Surface Enhanced Raman Spectroscopy Platform Technology to Detect Cardiac Biomarkers of Myocardial Infarction 

    E-Print Network [OSTI]

    Benford, Melodie Elane

    2013-04-24

    to include cardiac markers as central to diagnosis. To address this clinical need, a sensitive microfluidic surface-enhanced Raman spectroscopy (SERS) nanochannel-based optical device is being developed for ultimate use as a point-of-care device...

  3. Quantification of soil organic carbon using mid- and near- DRIFT spectroscopy 

    E-Print Network [OSTI]

    Kang, Misun

    2004-09-30

    ) and oxidizable organic carbon (OCWB) fraction were calibrated and predicted by mid- and near-DRIFT spectroscopy in combination with partial least squares (PLS) regression method. PLS regression is a multivariate calibration method that can decompose spectral data...

  4. Near-infrared spectroscopy for the measurement of glucose in an integrated rotating wall vessel 

    E-Print Network [OSTI]

    Galvan, Mark

    1994-01-01

    culture media cannot fulfill these requirements. Therefore a near-infrared spectroscopy system is proposed that can potentially perform the required measurements on-line and without any interaction with the cell culture media. Two types of solutions...

  5. FT-IR spectroscopy technology, market evolution and future strategies of Bruker Optics Inc.

    E-Print Network [OSTI]

    Higdon, Thomas (Thomas Charles)

    2010-01-01

    This thesis explores the technology and market evolution of FT-IR spectroscopy over its nearly forty year history to aid in determining future product design and marketing strategies for an industry-leading firm, Bruker ...

  6. Proceedings of the Fourteenth International Conference on Time-Resolved Vibrational Spectroscopy (TRVS XIV)

    E-Print Network [OSTI]

    Tokmakoff, Andrei

    2011-08-31

    Abstracts of presentations made at the Fourteenth International Conference on Time-Resolved Vibrational Spectroscopy (TRVS XIV) held May 9-14, 2009 in Meredith, New Hampshire. TRVS is a series of biennial conferences ...

  7. Gravitational resonance spectroscopy with an oscillating magnetic field gradient in the GRANIT flow through arrangement

    E-Print Network [OSTI]

    G. Pignol; S. Baessler; V. V. Nesvizhevsky; K. Protasov; D. Rebreyend; A. Yu. Voronin

    2014-08-05

    Gravitational resonance spectroscopy consists in measuring the energy spectrum of bouncing ultracold neutrons above a mirror by inducing resonant transitions between different discrete quantum levels. We discuss how to induce the resonances with a flow through arrangement in the GRANIT spectrometer, excited by an oscillating magnetic field gradient. The spectroscopy could be realized in two distinct modes (so called DC and AC) using the same device to produce the magnetic excitation. We present calculations demonstrating the feasibility of the newly proposed AC mode.

  8. Using Visible and Near Infrared Diffuse Reflectance Spectroscopy to Characterize and Classify Soil Profiles 

    E-Print Network [OSTI]

    Wilke, Katrina Margarette

    2011-10-21

    AND NEAR INFRARED DIFFUSE REFLECTANCE SPECTROSCOPY TO CHARACTERIZE AND CLASSIFY SOIL PROFILES A Thesis by KATRINA MARGARETTE WILKE Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements... for the degree of MASTER OF SCIENCE August 2010 Major Subject: Soil Science USING VISIBLE AND NEAR INFRARED DIFFUSE REFLECTANCE SPECTROSCOPY TO CHARACTERIZE AND CLASSIFY SOIL PROFILES A Thesis by KATRINA MARGARETTE WILKE Submitted...

  9. Near-infrared integral-field spectroscopy of HD209458b

    E-Print Network [OSTI]

    Daniel Angerhausen; Alfred Krabbe; Christof Iserlohe

    2006-05-12

    We present first results of an exploratory study to use integral field spectroscopy to observe extrasolar planets. We focus on transiting "Hot Jupiters" and emphasize the importance of observing strategy and exact timing. We demonstrate how integral field spectroscopy compares with other spectroscopic techniques currently applied. We have tested our concept with a time series observation of HD209458b obtained with SINFONI at the VLT during a superior conjunction.

  10. Determination of delaminated area of coated steel using electrochemical impedance spectroscopy 

    E-Print Network [OSTI]

    Alwohaibi, Mohammed Abdullaziz

    1992-01-01

    DETERMINATION OF DELAMINATED AREA OF COATED STEEL USING ELECTROCHEMICAL IMPEDANCE SPECTROSCOPY A Thesis by MOHAMMED ABDULLAZIZ ALWOHAIBI Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment... of the requirement for the degree of MASTER OF SCIENCE December 1992 Major Subject: Chemical Engineering DETERMINATION OF DELAMINATED AREA OF COATED STEEL USING ELECTROCHEMICAL IMPEDANCE SPECTROSCOPY A Thesis by MOHAMMED ABDULLAZIZ ALWOHAIBI Appmved...

  11. 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.

  12. Excitation and Far field Spectroscopy of surface plasmons in Gold nanostructures 

    E-Print Network [OSTI]

    Peng, Siying

    2011-08-08

    -1 EXCITATION AND FAR FIELD SPECTROSCOPY OF SURFACE PLASMONS IN GOLD NANOSTRUCTURES Major: Physics and Mathematics April 2010 Submitted to the Honors Programs Office Texas A&M University in partial fulfillment of the requirements for the designation... as HONORS UNDERGRADUATE RESEARCH FELLOW An Honors Fellows Thesis by SIYING PENG EXCITATION AND FAR FIELD SPECTROSCOPY OF SURFACE PLASMONS IN GOLD NANOSTRUCTURES Approved by: Research Advisor...

  13. NON-INVASIVE OPTICAL DETECTION OF EPITHELIAL CANCER USING OBLIQUE INCIDENCE DIFFUSE REFLECTANCE SPECTROSCOPY 

    E-Print Network [OSTI]

    Garcia-Uribe, Alejandro

    2010-01-16

    DETECTION OF EPITHELIAL CANCER USING OBLIQUE INCIDENCE DIFFUSE REFLECTANCE SPECTROSCOPY A Dissertation by ALEJANDRO GARCIA URIBE Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements... for the degree of DOCTOR OF PHILOSOPHY May 2009 Major Subject: Electrical Engineering NON-INVASIVE OPTICAL DETECTION OF EPITHELIAL CANCER USING OBLIQUE INCIDENCE DIFFUSE REFLECTANCE SPECTROSCOPY A Dissertation by ALEJANDRO GARCIA URIBE...

  14. J. Phys. B: At. Mol. Phys. 16 (1983) 2119-2133. Printed in Great Britain Forward scattering (polarisation spectroscopy) of resonance

    E-Print Network [OSTI]

    Zakrzewski, Kuba

    1983-01-01

    . Introduction Polarisation spectroscopy (PS), a very efficientmethod of high-resolution laser spectros- copy

  15. Optical Spectroscopy of 2MASS Color-Selected Ultracool Subdwarfs

    E-Print Network [OSTI]

    Adam J. Burgasser; Kelle L. Cruz; J. Davy Kirkpatrick

    2006-10-03

    We present Gemini GMOS and Magellan LDSS-3 optical spectroscopy for seven ultracool subdwarf candidates color-selected from the Two Micron All Sky Survey. Five are identified as late-type subdwarfs, including the previously reported sdM9.5 SSSPM 1013-1356 and L subdwarf 2MASS 1626+3925, and a new sdM8.5 2MASS 0142+0523. 2MASS 1640+1231 exhibits spectral features intermediate between a late-type M dwarf and subdwarf, similar to the previously identified high proper motion star SSSPM 1444-2019, and we classify both sources as mild subdwarfs, d/sdM9. 2MASS 1227-0447 is a new ultracool extreme subdwarf, spectral type esdM7.5. Spectral model fits yield metallicities that are consistent with these metallicity classifications. Effective temperatures track with numerical subtype within a metallicity class, although they are not equivalent across metallicity classes. As a first attempt to delineate subtypes in the L subdwarf regime we classify 2MASS 1626+3925 and the previously identified 2MASS 0532+8246 as sdL4 and sdL7, respectively, to reflect their similarity to equivalently classified, solar metallicity L-type field dwarfs over the 7300-9000 A region. We also detail preliminary criteria for distinguishing L subdwarf optical spectra as a roadmap for defining this new spectral class. The strong TiO bands and Ca I and Ti I lines in the spectrum of 2MASS 1626+3925 provide further evidence that condensate formation may be inhibited in metal-deficient L subdwarfs. We conclude with a compendium of currently known, optically classified ultracool subdwarfs.

  16. Nanocrystalline zinc ferrite films studied by magneto-optical spectroscopy

    SciTech Connect (OSTI)

    Lišková-Jakubisová, E. Viš?ovský, Š.; Široký, P.; Hrabovský, D.; Pištora, 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 ?20–30?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.

  17. 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.

  18. Quantum Field Effects in Stationary Electron Spin Resonance Spectroscopy

    E-Print Network [OSTI]

    Dmitri Yerchuck; Vyacheslav Stelmakh; Yauhen Yerchak; Alla Dovlatova

    2015-01-28

    It is proved on the example of electron spin resonance (ESR) studies of anthracites, that by strong electron-photon and electron-phonon interactions the formation of the coherent system of the resonance phonons takes place. The acoustic quantum Rabi oscillations were observed for the first time in ESR-spectroscopy. Its Rabi frequency value on the first damping stage was found to be equal 920.6 kHz, being to be independent on the microwave power level in the range 20 - 6 dB [0 dB corresponds to 100 mW]. By the subsequent increase of the microwave power the stepwise transition to the phenomenon of nonlinear quantum Rabi oscillations, characterised by splitting of the oscillation group of lines into two subgroups with doubling of the total lines' number takes place. Linewidth of an individual oscillation line becomes approximately the twofold narrower, being to be equal the only to $0.004 \\pm 0.001$ G. Along with the absorption process of EM-field energy the emission process was observed. It was found, that the emission process is the realization of the acoustic spin resonance, the source of acoustic wave power in which is the system of resonance phonons, accumulated in the samples by the registration with AFC. It has been found, that the lifetime of coherent state of a collective subsystem of resonance phonons in anthracites is very long and even by room temperature it is evaluated by the value exceeding 4.6 minutes. The model of new kinds of instantons was proposed. They are considered to be similar in the mathematical structure to Su-Schrieffer-Heeger solitons with "propagation" direction along time $t$-axis instead of space $z$-axis. The proof, that the superconductivity state in the anthracite samples studied is produced at the room temperature in ESR conditions in the accordance with the theory of the quantised acoustic field, has experimentally been obtained.

  19. Applications and advances of positron beam spectroscopy: appendix a

    SciTech Connect (OSTI)

    Howell, R. H., LLNL

    1997-11-05

    Over 50 scientists from DOE-DP, DOE-ER, the national laboratories, academia and industry attended a workshop held on November 5-7, 1997 at Lawrence Livermore National Laboratory jointly sponsored by the DOE-Division of Materials Science, The Materials Research Institute at LLNL and the University of California Presidents Office. Workshop participants were charged to address two questions: Is there a need for a national center for materials analysis using positron techniques and can the capabilities at Lawrence Livermore National Laboratory serve this need. To demonstrate the need for a national center the workshop participants discussed the technical advantages enabled by high positron currents and advanced measurement techniques, the role that these techniques will play in materials analysis and the demand for the data. There were general discussions lead by review talks on positron analysis techniques, and their applications to problems in semiconductors, polymers and composites, metals and engineering materials, surface analysis and advanced techniques. These were followed by focus sessions on positron analysis opportunities in these same areas. Livermore now leads the world in materials analysis capabilities by positrons due to developments in response to demands of science based stockpile stewardship. There was a detailed discussion of the LLNL capabilities and a tour of the facilities. The Livermore facilities now include the worlds highest current beam of keV positrons, a scanning pulsed positron microprobe under development capable of three dimensional maps of defect size and concentration, an MeV positron beam for defect analysis of large samples, and electron momentum spectroscopy by positrons. This document is a supplement to the written summary report. It contains a complete schedule, list of attendees and the vuegraphs for the presentations in the review and focus sessions.

  20. 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.

  1. Spectroscopy of the transition state: Elementary reactions of the hydroxyl radical studied by photoelectron spectroscopy of O (H2O) and H3O2

    E-Print Network [OSTI]

    Neumark, Daniel M.

    Spectroscopy of the transition state: Elementary reactions of the hydroxyl radical studied to study the unstable neutral complexes involved in two fundamental re- actions of the hydroxyl radical OH H2OH2O OH, 1 OH OHO 3 P H2O. 2 The role of the hydroxyl radical as a propagator of chain reactions

  2. Thermal decomposition of CH{sub 3}CHO studied by matrix infrared spectroscopy and photoionization mass spectroscopy

    SciTech Connect (OSTI)

    Vasiliou, AnGayle K. [Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309-0215 (United States); National Renewable Energy Laboratory, 1617 Cole Blvd., Golden, Colorado 80401 (United States); Piech, Krzysztof M.; Reed, Beth; Ellison, G. Barney [Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309-0215 (United States); Zhang Xu [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, California 91109-8099 (United States); Nimlos, Mark R. [National Renewable Energy Laboratory, 1617 Cole Blvd., Golden, Colorado 80401 (United States); Ahmed, Musahid; Golan, Amir; Kostko, Oleg [Chemical Sciences Division, LBNL MS 6R-2100, Berkeley, California 94720 (United States); Osborn, David L. [Combustion Research Facility, Sandia National Laboratories, P.O. Box 969 MS 9055, Livermore, California 94551-0969 (United States); David, Donald E. [Integrated Instrument Design Facility, CIRES, University of Colorado, Boulder, Colorado 80309-0216 (United States); Urness, Kimberly N.; Daily, John W. [Center for Combustion and Environmental Research, Department of Mechanical Engineering, University of Colorado at Boulder, Boulder, Colorado 80309-0427 (United States); Stanton, John F. [Institute for Theoretical Chemistry, Department of Chemistry, University of Texas, Austin, Texas 78712 (United States)

    2012-10-28

    A heated SiC microtubular reactor has been used to decompose acetaldehyde and its isotopomers (CH{sub 3}CDO, CD{sub 3}CHO, and CD{sub 3}CDO). The pyrolysis experiments are carried out by passing a dilute mixture of acetaldehyde (roughly 0.1%-1%) entrained in a stream of a buffer gas (either He or Ar) through a heated SiC reactor that is 2-3 cm long and 1 mm in diameter. Typical pressures in the reactor are 50-200 Torr with the SiC tube wall temperature in the range 1200-1900 K. Characteristic residence times in the reactor are 50-200 {mu}s after which the gas mixture emerges as a skimmed molecular beam at a pressure of approximately 10 {mu}Torr. The reactor has been modified so that both pulsed and continuous modes can be studied, and results from both flow regimes are presented. Using various detection methods (Fourier transform infrared spectroscopy and both fixed wavelength and tunable synchrotron radiation photoionization mass spectrometry), a number of products formed at early pyrolysis times (roughly 100-200 {mu}s) are identified: H, H{sub 2}, CH{sub 3}, CO, CH{sub 2}=CHOH, HC{identical_to}CH, H{sub 2}O, and CH{sub 2}=C=O; trace quantities of other species are also observed in some of the experiments. Pyrolysis of rare isotopomers of acetaldehyde produces characteristic isotopic signatures in the reaction products, which offers insight into reaction mechanisms that occur in the reactor. In particular, while the principal unimolecular processes appear to be radical decomposition CH{sub 3}CHO (+M) {yields} CH{sub 3}+ H + CO and isomerization of acetaldehyde to vinyl alcohol, it appears that the CH{sub 2}CO and HCCH are formed (perhaps exclusively) by bimolecular reactions, especially those involving hydrogen atom attacks.

  3. 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.

  4. 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.

  5. Laser spectroscopy and dynamics of transient species. Final progress report, June 1, 1986--May 31, 1996

    SciTech Connect (OSTI)

    Clouthier, D.J.

    1996-05-01

    This project involved the study of the spectroscopy and excited state dynamics of transient molecules, particularly sulfur- and/or oxygen-containing species. The identification and study of sulfur species is important in understanding their role in combustion processes, as sulfur compounds are often present in fuels. The oxygen-containing species chosen for study were new systems whose spectroscopy was only poorly documented. The major experimental techniques employed in this work were pyrolysis jet spectroscopy, intracavity dye laser spectroscopy and high-resolution Fourier transform infrared spectroscopy. Since many of the species had not been previously studied by laser techniques, much effort was devoted to determining methods for producing, identifying and studying them. We have been very successful in a number of cases and have developed some new experimental techniques. Lists of publications resulting from the work and graduate and postdoctoral students supported during this project are included at the end of this report. Summaries of the results of some specific aspects of the project are given below.

  6. 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.

  7. Electron beam exposure mechanisms in hydrogen silsesquioxane investigated by vibrational spectroscopy and in-situ electron beam induced desorption

    E-Print Network [OSTI]

    Olynick, D.L.

    2010-01-01

    Electron beam exposure mechanisms in hydrogen silsesquioxanespectroscopy and in-situ electron beam induced desorption.Infrared) and electron beam desorption spectroscopy (EBDS).

  8. SPECTROSCOPY IN CRYOCRYSTALS AND MATRICES Time-resolved CARS measurements of the vibrational decoherence of I2 isolated

    E-Print Network [OSTI]

    Apkarian, V. Ara

    SPECTROSCOPY IN CRYOCRYSTALS AND MATRICES Time-resolved CARS measurements of the vibrational report.1 Succinctly, the forward BOX- CARS geometry is adopted, using three noncollinear laser pulses

  9. Combining multivariate analysis and monosaccharide composition modeling to identify plant cell wall variations by Fourier Transform Near Infrared spectroscopy

    E-Print Network [OSTI]

    2011-01-01

    spectroscopy coupled with multivariate data analysis. I.Krzanowski WJ: Principles of multivariate analysis: a user’set al. : Combining multivariate analysis and monosaccharide

  10. Combining multivariate analysis and monosaccharide composition modeling to identify plant cell wall variations by Fourier Transform Near Infrared spectroscopy.

    E-Print Network [OSTI]

    2011-01-01

    spectroscopy coupled with multivariate data analysis. I.Krzanowski WJ: Principles of multivariate analysis: a user’set al. : Combining multivariate analysis and monosaccharide

  11. Single-Beam Coherent Raman Spectroscopy and Microscopy via Spectral Notch Shaping

    E-Print Network [OSTI]

    Katz, Ori; Grinvald, Eran; Silberberg, Yaron

    2010-01-01

    Raman spectroscopy is one of the key techniques in the study of vibrational modes and molecular structures. In Coherent Anti-Stokes Raman Scattering (CARS) spectroscopy, a molecular vibrational spectrum is resolved via the third-order nonlinear interaction of pump, Stokes and probe photons, typically using a complex experimental setup with multiple beams and laser sources. Although CARS has become a widespread technique for label-free chemical imaging and detection of contaminants, its multi-source, multi-beam experimental implementation is challenging. In this work we present a simple and easily implementable scheme for performing single-beam CARS spectroscopy and microscopy using a single femtosecond pulse, shaped by a tunable narrowband notch filter. As a substitute for multiple sources, the single broadband pulse simultaneously provides the pump, Stokes and probe photons, exciting a broad band of vibrational levels. High spectroscopic resolution is obtained by utilizing a tunable spectral notch, shaped wi...

  12. 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.

  13. 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.

  14. Long-slit and Fabry-Perot spectroscopy of collisional ring galaxy Arp 10

    E-Print Network [OSTI]

    A. V. Moiseev; D. V. Bizyaev; E. I. Vorobyov

    2005-01-27

    We present results of Fabry-Perot and long-slit spectroscopy of the peculiar galaxy Arp 10. The ionized gas velocity field shows evidence for significant radial motions in both outer and inner galactic rings. Long-slit spectroscopy reveals gradients of age and metallicity of stellar population in agreement with the propagating nature of star formation in the galaxy. We present strong evidence that a small ``knot'' at 5 arcsec from the center of Arp 10 is its dwarf elliptic satellite, the most probable ``intruder'' responsible for triggering the expanding rings in Arp 10.

  15. Spectroscopy and BVI photometry of the young open cluster NGC 6604

    E-Print Network [OSTI]

    R. Barbon; G. Carraro; U. Munari; T. Zwitter; L. Tomasella

    2000-04-03

    BVI photometry (from South Africa Astron. Obs.), Echelle high resolution spectroscopy and AFOSC integral field spectroscopy (from Asiago, Italy) of the young open cluster NGC 6604 are presented. Age, distance, reddening, membership, radial and rotational velocities are derived and discussed. An age of 5 million years, a distance of 1.7 kpc and a reddening E(B-V)=1.02 are found. The cluster radial velocity is in agreement with the Hron (1987) model for the Galaxy disk rotation. Pre-ZAMS objects are not present down to M_V = +1.5 mag.

  16. 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.

  17. 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.

  18. 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.

  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.