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Title: Differential nonreactive scattering of He*(2 /sup 1/S, 2 /sup 3/S) by D/sub 2/ and H/sub 2/: Anisotropic optical potentials and comparison with ab initio theory

Abstract

Angular distributions of He*(2 /sup 1/S, 2 /sup 3/S) scattered by D/sub 2/ and H/sub 2/ measured in crossed supersonic molecular beams at collision energies in the range 1.0--2.4 kcal/mol are analyzed to yield anisotropic optical potentials that simultaneously reproduce these data along with quenching rates and ionization cross sections. Comparison with ab initio calculations of the potentials by Cohen and Lane and Hickman, Isaacson, and Miller shows very good agreement. The results are combined with one-electron model potential calculations to probe the nuclear and electronic dynamics involved in these collisions. Quenching or Penning ionization is found to occur mainly through broadside attack of He* on H/sub 2/, despite the fact that the occupied sigma/sub g/ orbital on H/sub 2/ has greater spatial extent along the bond axis than perpendicular to it. An implication is that Penning ionization electron spectroscopy (PIES) experiments on larger molecules cannot be interpreted simply on the basis of van der Waals radii and spatial extent of various molecular orbitals; the nature of the excited-state potential surface may play a dominant role in determining these spectra.

Authors:
;
Publication Date:
Research Org.:
Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260
OSTI Identifier:
5991926
Alternate Identifier(s):
OSTI ID: 5991926
Resource Type:
Journal Article
Journal Name:
J. Chem. Phys.; (United States)
Additional Journal Information:
Journal Volume: 82:6
Country of Publication:
United States
Language:
English
Subject:
74 ATOMIC AND MOLECULAR PHYSICS; DEUTERIUM; ATOM-MOLECULE COLLISIONS; HELIUM; HYDROGEN; ANGULAR DISTRIBUTION; IONIZATION; MOLECULAR BEAMS; RADIATIONLESS DECAY; ATOM COLLISIONS; BEAMS; COLLISIONS; DE-EXCITATION; DISTRIBUTION; ELEMENTS; ENERGY TRANSFER; ENERGY-LEVEL TRANSITIONS; FLUIDS; GASES; HYDROGEN ISOTOPES; ISOTOPES; LIGHT NUCLEI; MOLECULE COLLISIONS; NONMETALS; NUCLEI; ODD-ODD NUCLEI; RARE GASES; STABLE ISOTOPES 640304* -- Atomic, Molecular & Chemical Physics-- Collision Phenomena

Citation Formats

Martin, D.W., and Siska, P.E. Differential nonreactive scattering of He*(2 /sup 1/S, 2 /sup 3/S) by D/sub 2/ and H/sub 2/: Anisotropic optical potentials and comparison with ab initio theory. United States: N. p., 1985. Web.
Martin, D.W., & Siska, P.E. Differential nonreactive scattering of He*(2 /sup 1/S, 2 /sup 3/S) by D/sub 2/ and H/sub 2/: Anisotropic optical potentials and comparison with ab initio theory. United States.
Martin, D.W., and Siska, P.E. Fri . "Differential nonreactive scattering of He*(2 /sup 1/S, 2 /sup 3/S) by D/sub 2/ and H/sub 2/: Anisotropic optical potentials and comparison with ab initio theory". United States.
@article{osti_5991926,
title = {Differential nonreactive scattering of He*(2 /sup 1/S, 2 /sup 3/S) by D/sub 2/ and H/sub 2/: Anisotropic optical potentials and comparison with ab initio theory},
author = {Martin, D.W. and Siska, P.E.},
abstractNote = {Angular distributions of He*(2 /sup 1/S, 2 /sup 3/S) scattered by D/sub 2/ and H/sub 2/ measured in crossed supersonic molecular beams at collision energies in the range 1.0--2.4 kcal/mol are analyzed to yield anisotropic optical potentials that simultaneously reproduce these data along with quenching rates and ionization cross sections. Comparison with ab initio calculations of the potentials by Cohen and Lane and Hickman, Isaacson, and Miller shows very good agreement. The results are combined with one-electron model potential calculations to probe the nuclear and electronic dynamics involved in these collisions. Quenching or Penning ionization is found to occur mainly through broadside attack of He* on H/sub 2/, despite the fact that the occupied sigma/sub g/ orbital on H/sub 2/ has greater spatial extent along the bond axis than perpendicular to it. An implication is that Penning ionization electron spectroscopy (PIES) experiments on larger molecules cannot be interpreted simply on the basis of van der Waals radii and spatial extent of various molecular orbitals; the nature of the excited-state potential surface may play a dominant role in determining these spectra.},
doi = {},
journal = {J. Chem. Phys.; (United States)},
number = ,
volume = 82:6,
place = {United States},
year = {1985},
month = {3}
}