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

Journal Article · Fri Mar 15 04:00:00 EST 1985 · J. Chem. Phys.; (United States)

OSTI ID:5991926

Martin, D W; Siska, P E

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.

• Research Organization: Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260
• OSTI ID: 5991926
• Journal Information: J. Chem. Phys.; (United States), Journal Name: J. Chem. Phys.; (United States) Vol. 82:6; ISSN JCPSA
• Country of Publication: United States
• Language: English

Related Subjects

640304* -- Atomic
Molecular & Chemical Physics-- Collision Phenomena
74 ATOMIC AND MOLECULAR PHYSICS
ANGULAR DISTRIBUTION
ATOM COLLISIONS
ATOM-MOLECULE COLLISIONS
BEAMS
COLLISIONS
DE-EXCITATION
DEUTERIUM
DISTRIBUTION
ELEMENTS
ENERGY TRANSFER
ENERGY-LEVEL TRANSITIONS
FLUIDS
GASES
HELIUM
HYDROGEN
HYDROGEN ISOTOPES
IONIZATION
ISOTOPES
LIGHT NUCLEI
MOLECULAR BEAMS
MOLECULE COLLISIONS
NONMETALS
NUCLEI
ODD-ODD NUCLEI
RADIATIONLESS DECAY
RARE GASES
STABLE ISOTOPES