Adiabatic long-range rotationally inelastic collisions in Li*/sub 2/(A /sup 1/. sigma. )--Xe: Experiment and theory

Journal Article · Sat Dec 15 04:00:00 EST 1984 · J. Chem. Phys.; (United States)

OSTI ID:6248540

Smith, N

A recent study of the velocity dependence of rotationally inelastic (RI) collision cross sections in Li(/sub 2/ --rare gas systems has shown the ..delta..equivalentj/sub f/-j/sub i/ = +- 2 cross sections in Li(/sub 2/--Xe to be exceptional in their large size and rising velocity dependence. A simple semiclassical time dependent perturbation treatment using the long-range R/sup -6/ dispersion potential will be shown to provide an excellent description of the magnitude and velocity dependence of these cross sections. The analysis explicitly accounts for the molecular rotation during the collision, which is shown to cause the substantial adiabatic reduction of these Vertical Bar..delta..Vertical Bar = 2 cross sections at lower velocity. The observation that almost all other RI collision cross sections in Li(/sub 2/--rare gas systems decrease with larger velocity suggests that long-range collisional contributions and rotationally adiabatic effects are not of general importance for these collisions. New experimental as well as theoretical investigations into vib-rotationally inelastic collisions in Li(/sub 2/--Xe suggest that vibrational inelasticity may have been previously mistaken for rotational adiabaticity when accounting for the general decrease in RI cross sections at larger j/sub i/.

• Research Organization: Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
• OSTI ID: 6248540
• Journal Information: J. Chem. Phys.; (United States), Journal Name: J. Chem. Phys.; (United States) Vol. 81:12; ISSN JCPSA
• Country of Publication: United States
• Language: English

Related Subjects

640304* -- Atomic
Molecular & Chemical Physics-- Collision Phenomena
74 ATOMIC AND MOLECULAR PHYSICS
ALKALI METALS
ATOM COLLISIONS
ATOM-MOLECULE COLLISIONS
COLLISIONS
DIMERS
ELEMENTS
ENERGY LEVELS
ENERGY-LEVEL TRANSITIONS
EXCITED STATES
FLUIDS
GASES
LITHIUM
METALS
MOLECULE COLLISIONS
NONMETALS
RARE GASES
ROTATIONAL STATES
XENON