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Title: Measurements of partial cross sections and photoelectron angular distributions for the photodetachment of Fe{sup -} and Cu{sup -} at visible photon wavelengths

Abstract

Photodetachment cross sections and the angular distributions of photoelectrons produced by the single-photon detachment of the transition metal negative ions Fe{sup -} and Cu{sup -} have been measured at four discrete photon wavelengths ranging from 457.9 to 647.1 nm (2.71-1.92 eV) using a crossed-beams laser photodetachment electron spectrometry (LPES) apparatus. Photodetachment cross sections were determined by comparing the photoelectron yields from the photodetachment of Fe{sup -} to those of Cu{sup -} and C{sup -}, which have known absolute photodetachment cross sections. Using the measured photodetachment cross sections, radiative electron attachment cross sections were calculated using the principle of detailed balance. Angular distributions were determined by measurements of laboratory frame, angle-, and energy-resolved photoelectrons as a function of the angle between the linear laser polarization vector and the momentum vector of the collected photoelectrons. Values of the asymmetry parameter have been determined by nonlinear least-squares fits to these angular distributions. The measured asymmetry parameters are compared to predictions of photodetachment models including Cooper and Zare's dipole approximation theory [J. Cooper and R. N. Zare, J. Chem. Phys. 48, 942 (1968)], and the angular momentum transfer theory developed by Fano and Dill [Phys. Rev. A 6, 185 (1972)].

Authors:
; ; ; ; ; ; ; ; ; ;  [1];  [2];  [2];  [2];  [2];  [2]
  1. Department of Physics and Nevada Terawatt Facility, MS 220, University of Nevada, Reno, Nevada 89557-0058 (United States)
  2. (United States)
Publication Date:
OSTI Identifier:
20982125
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. A; Journal Volume: 75; Journal Issue: 2; Other Information: DOI: 10.1103/PhysRevA.75.022711; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
74 ATOMIC AND MOLECULAR PHYSICS; ANGULAR DISTRIBUTION; ANGULAR MOMENTUM TRANSFER; APPROXIMATIONS; ASYMMETRY; CARBON IONS; COLLIDING BEAMS; COPPER IONS; CROSS SECTIONS; DIPOLES; ELECTRON ATTACHMENT; ELECTRON DETACHMENT; ELECTRONS; IRON IONS; LEAST SQUARE FIT; NONLINEAR PROBLEMS; PHOTOELECTRON SPECTROSCOPY; PHOTON-ATOM COLLISIONS; PHOTONS; POLARIZATION; WAVELENGTHS

Citation Formats

Covington, A. M., Duvvuri, Srividya S., Emmons, E. D., Kraus, R. G., Williams, W. W., Thompson, J. S., Calabrese, D., Carpenter, D. L., Collier, R. D., Kvale, T. J., Davis, V. T., Department of Physics, Sierra College, Rocklin, California 95677, National Renewable Energy Laboratory, Golden, Colorado 80401-3393, Department of Physics, Western Nevada Community College, Carson City, Nevada 89703, Department of Physics and Astronomy, The University of Toledo, Toledo, Ohio 43606-3390, and Test Support Division, Defense Threat Reduction Agency, West Desert Test Center, Dugway, Utah 84022-5000. Measurements of partial cross sections and photoelectron angular distributions for the photodetachment of Fe{sup -} and Cu{sup -} at visible photon wavelengths. United States: N. p., 2007. Web. doi:10.1103/PHYSREVA.75.022711.
Covington, A. M., Duvvuri, Srividya S., Emmons, E. D., Kraus, R. G., Williams, W. W., Thompson, J. S., Calabrese, D., Carpenter, D. L., Collier, R. D., Kvale, T. J., Davis, V. T., Department of Physics, Sierra College, Rocklin, California 95677, National Renewable Energy Laboratory, Golden, Colorado 80401-3393, Department of Physics, Western Nevada Community College, Carson City, Nevada 89703, Department of Physics and Astronomy, The University of Toledo, Toledo, Ohio 43606-3390, & Test Support Division, Defense Threat Reduction Agency, West Desert Test Center, Dugway, Utah 84022-5000. Measurements of partial cross sections and photoelectron angular distributions for the photodetachment of Fe{sup -} and Cu{sup -} at visible photon wavelengths. United States. doi:10.1103/PHYSREVA.75.022711.
Covington, A. M., Duvvuri, Srividya S., Emmons, E. D., Kraus, R. G., Williams, W. W., Thompson, J. S., Calabrese, D., Carpenter, D. L., Collier, R. D., Kvale, T. J., Davis, V. T., Department of Physics, Sierra College, Rocklin, California 95677, National Renewable Energy Laboratory, Golden, Colorado 80401-3393, Department of Physics, Western Nevada Community College, Carson City, Nevada 89703, Department of Physics and Astronomy, The University of Toledo, Toledo, Ohio 43606-3390, and Test Support Division, Defense Threat Reduction Agency, West Desert Test Center, Dugway, Utah 84022-5000. Thu . "Measurements of partial cross sections and photoelectron angular distributions for the photodetachment of Fe{sup -} and Cu{sup -} at visible photon wavelengths". United States. doi:10.1103/PHYSREVA.75.022711.
@article{osti_20982125,
title = {Measurements of partial cross sections and photoelectron angular distributions for the photodetachment of Fe{sup -} and Cu{sup -} at visible photon wavelengths},
author = {Covington, A. M. and Duvvuri, Srividya S. and Emmons, E. D. and Kraus, R. G. and Williams, W. W. and Thompson, J. S. and Calabrese, D. and Carpenter, D. L. and Collier, R. D. and Kvale, T. J. and Davis, V. T. and Department of Physics, Sierra College, Rocklin, California 95677 and National Renewable Energy Laboratory, Golden, Colorado 80401-3393 and Department of Physics, Western Nevada Community College, Carson City, Nevada 89703 and Department of Physics and Astronomy, The University of Toledo, Toledo, Ohio 43606-3390 and Test Support Division, Defense Threat Reduction Agency, West Desert Test Center, Dugway, Utah 84022-5000},
abstractNote = {Photodetachment cross sections and the angular distributions of photoelectrons produced by the single-photon detachment of the transition metal negative ions Fe{sup -} and Cu{sup -} have been measured at four discrete photon wavelengths ranging from 457.9 to 647.1 nm (2.71-1.92 eV) using a crossed-beams laser photodetachment electron spectrometry (LPES) apparatus. Photodetachment cross sections were determined by comparing the photoelectron yields from the photodetachment of Fe{sup -} to those of Cu{sup -} and C{sup -}, which have known absolute photodetachment cross sections. Using the measured photodetachment cross sections, radiative electron attachment cross sections were calculated using the principle of detailed balance. Angular distributions were determined by measurements of laboratory frame, angle-, and energy-resolved photoelectrons as a function of the angle between the linear laser polarization vector and the momentum vector of the collected photoelectrons. Values of the asymmetry parameter have been determined by nonlinear least-squares fits to these angular distributions. The measured asymmetry parameters are compared to predictions of photodetachment models including Cooper and Zare's dipole approximation theory [J. Cooper and R. N. Zare, J. Chem. Phys. 48, 942 (1968)], and the angular momentum transfer theory developed by Fano and Dill [Phys. Rev. A 6, 185 (1972)].},
doi = {10.1103/PHYSREVA.75.022711},
journal = {Physical Review. A},
number = 2,
volume = 75,
place = {United States},
year = {Thu Feb 15 00:00:00 EST 2007},
month = {Thu Feb 15 00:00:00 EST 2007}
}
  • No abstract prepared.
  • The spectral dependence of the angular distributions of photoelectrons produced by the single-photon detachment of Al{sup {minus}}, Si{sup {minus}}, and P{sup {minus}} ions has been measured at five discrete photon wavelengths ranging from 457.9 to 647.1 nm (2.71{endash}1.92 eV) using a crossed laser-ion beam apparatus. Values of the asymmetry parameter have been determined by fits to the photoelectron yield as a function of the angle between the laser polarization vector and the linear momentum vector of the collected photoelectrons. The experimental results for Al{sup {minus}} are compared with a recent theoretical calculation [C. N. Liu and A. F. Starace, Bull.more » Am. Phys. Soc. {bold 42}, 1026 (1997)] and are found to be in good agreement. {copyright} {ital 1997} {ital The American Physical Society}« less
  • Photodetached d-electron angular distributions have been measured for the processes V{sup -}(3d{sup 4}4s{sup 2}){sup 5}D+h{nu}{yields}V(3d{sup 3}4s{sup 2}){sup 4}F+e{sup -}, V{sup -}(3d{sup 4}4s{sup 2}){sup 5}D+h{nu}{yields}V(3d{sup 3}4s{sup 2}){sup 4}P+e{sup -}, and at discrete wavelengths in the region 457.9-647.1 nm using the laser photoelectron spectroscopy technique. Photoelectron yields were obtained by measuring the laboratory frame energy spectra of photodetached electrons as a function of the angle between the velocity vector of the outgoing photoelectrons and the polarization direction of the linearly polarized photon beam. A nonlinear curve-fitting routine was used to extract the value of the asymmetry parameter for a particular transition atmore » fixed photon energies. Asymmetry parameters are also reported for photodetached s electrons in the transitions V{sup -}(3d{sup 4}4s{sup 2}){sup 5}D+h{nu}{yields}V(3d{sup 4}4s){sup 6}D+e{sup -} and V{sup -}(3d{sup 4}4s{sup 2}){sup 5}D+h{nu}{yields}V(3d{sup 4}4s){sup 4}D+e{sup -} at four photon energies.« less
  • The first photoelectron spectra of AgF{sup −} are recorded over the energy range 1.61–1.85 eV using the velocity map imaging technique. The resolved vibrational structure of the AgF X′, v′ ← AgF{sup −} X″, v″ = 0 band yields an AgF electron affinity of 1.46 ± 0.01 eV and vibrational frequency of 500 ± 40 cm{sup −1}. For the v′ = 2, 3, 4 channels, the photodetachment cross sections and angular distributions undergo rapid changes over a narrow electron kinetic energy range in the region of 50 meV (approximately 13 meV below the opening of the next vibrational channel). Thismore » is consistent with Fano-like behavior indicating autodetachment following excitation to a resonant anion state lying in the detachment continuum. EOM-CCSD calculations reveal this to be a dipole bound state. The consistency of the detachment data with the vibrational autodetachment propensity rule Δv = −1 shows that the autodetachment results from breakdown of the Born-Oppenheimer approximation, coupling the vibrational and electronic degrees of freedom.« less
  • We report total and differential cross sections for photodetachment from negative ions using Dyson orbitals calculated from equation-of-motion coupled-cluster wave functions and free wave description of the detached electron. The energy dependence of the cross sections is reproduced well, however, the accuracy of absolute values varies. For F{sup -}, C{sup -}, NH{sub 2}{sup -}, and H{sup -}, the calculated cross sections are within the error bars from the experimental values, whereas the errors for Li{sup -} and OH{sup -} are about 20%. The largest errors are observed for O{sup -} and O{sub 2}{sup -} for which the calculated cross sectionsmore » differ from the experimental ones by factors of 3 and 2, respectively. Calculated anisotropy parameters for atomic anions exhibit too slow decrease, which suggests that the diffuseness of the computed Dyson orbitals is underestimated. Moreover, in the asymptotic region, the orbitals exhibit artifactual oscillations probably due to the limitations of Gaussian basis sets. The analysis of the trends in the experimental anisotropy parameters suggests that the interaction of the detached electron with the core, which is neglected in the present model, is important.« less