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Title: Photoelectron wave function in photoionization: Plane wave or Coulomb wave? [Does photoionization of neutral targets produce Coulomb or plane waves?]

The calculation of absolute total cross sections requires accurate wave functions of the photoelectron and of the initial and final states of the system. The essential information contained in the latter two can be condensed into a Dyson orbital. We employ correlated Dyson orbitals and test approximate treatments of the photoelectron wave function, that is, plane and Coulomb waves, by comparing computed and experimental photoionization and photodetachment spectra. We find that in anions, a plane wave treatment of the photoelectron provides a good description of photodetachment spectra. For photoionization of neutral atoms or molecules with one heavy atom, the photoelectron wave function must be treated as a Coulomb wave to account for the interaction of the photoelectron with the +1 charge of the ionized core. For larger molecules, the best agreement with experiment is often achieved by using a Coulomb wave with a partial (effective) charge smaller than unity. This likely derives from the fact that the effective charge at the centroid of the Dyson orbital, which serves as the origin of the spherical wave expansion, is smaller than the total charge of a polyatomic cation. Finally, the results suggest that accurate molecular photoionization cross sections can be computed withmore » a modified central potential model that accounts for the nonspherical charge distribution of the core by adjusting the charge in the center of the expansion.« less
Authors:
 [1] ;  [1] ;  [2] ;  [3] ;  [2] ;  [1]
  1. Univ. of Southern California, Los Angeles, CA (United States)
  2. The Univ. of Texas, Austin, TX (United States)
  3. Sandia National Lab. (SNL-CA), Livermore, CA (United States)
Publication Date:
Report Number(s):
SAND-2016-10082J
Journal ID: ISSN 1948-7185; 649567
Grant/Contract Number:
AC04-94AL85000; FG02-05ER15685; FG02-07ER15884
Type:
Published Article
Journal Name:
Journal of Physical Chemistry Letters
Additional Journal Information:
Journal Volume: 6; Journal Issue: 22; Journal ID: ISSN 1948-7185
Publisher:
American Chemical Society
Research Org:
Sandia National Lab. (SNL-CA), Livermore, CA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; cross sections; Dyson orbital; effective charge; EOM-CC; Franck−Condon factors; photodetachment
OSTI Identifier:
1250177
Alternate Identifier(s):
OSTI ID: 1341397