Quantum studies of inelastic collisions of O/sub 2/(X-italic /sup 3/. sigma. /sup -//sub g-italic/) with He: Polarization effects and collisional propensity rules

Journal Article · Mon Sep 01 04:00:00 EDT 1986 · J. Chem. Phys.; (United States)

OSTI ID:5522215

Corey, G C; Alexander, M H; Schaefer, J

We investigate rotationally inelastic cross sections of O/sub 2/(X-italic /sup 3/..sigma../sup -//sub g-italic/) with He at a collision energy of 27 meV. Theoretical cross sections obtained from close-coupled (CC) calculations are compared with results from the infinite-order sudden (IOS) approximation. Both the CC and IOS fine-structure state-resolved cross sections exhibit a strong ..delta..N-italic = ..delta..J-italic F-italic/sub i-italic/ conserving collisional propensity. An analysis of the general expression for state-resolved cross sections in terms of spin-independent tensor opacities clearly establishes, without the introduction of dynamical approximations, the direct connection between this propensity rule and the collisional propensity for the conservation of the orientation of the nuclear rotational angular momentum vector N. In the low-N-italic limit, F-italic/sub i-italic/ changing O/sub 2/--He collisions are much more strongly depolarizing than collisions that conserve the F-italic/sub i-italic/ symmetry level. This enhanced collisional depolarization of an initial distribution of the total molecular angular momentum vector J is related to the collisional reorientation of N that must occur in F-italic/sub i-italic/ changing transitions.

• Research Organization: Department of Chemistry, University of Maryland, College Park, Maryland 20742
• OSTI ID: 5522215
• Journal Information: J. Chem. Phys.; (United States), Journal Name: J. Chem. Phys.; (United States) Vol. 85:5; ISSN JCPSA
• Country of Publication: United States
• Language: English

Related Subjects

640304* -- Atomic
Molecular & Chemical Physics-- Collision Phenomena
74 ATOMIC AND MOLECULAR PHYSICS
ATOM COLLISIONS
ATOM-MOLECULE COLLISIONS
COLLISIONS
CROSS SECTIONS
ELEMENTS
ENERGY LEVELS
ENERGY-LEVEL TRANSITIONS
EXCITED STATES
FLUIDS
GASES
HELIUM
MOLECULE COLLISIONS
NONMETALS
OXYGEN
POLARIZATION
RARE GASES
ROTATIONAL STATES
SUDDEN APPROXIMATION