Velocity dependence of rotationally inelastic collisions: /sup 7/Li(/sub 2/(A /sup 1/. sigma. ) +Ne, Ar, and Xe

Journal Article · Wed Aug 01 04:00:00 EDT 1984 · J. Chem. Phys.; (United States)

OSTI ID:6661332

Smith, N; Scott, T P; Pritchard, D E

We present velocity-selected measurements of the cross sections for rotationally inelastic collisions of /sup 7/Li(/sub 2/(A /sup 1/..sigma..) with Xe, Ar, and Ne, with various pairs of initial and final rotational levels, j/sub i/ and j/sub f/: Li(/sub 2/(v/sub i/ = 9, j/sub i/) +X..-->..Li(/sub 2/(v/sub f/ = 9, j/sub f/ = j/sub i/+..delta..)+X. For each target gas measurements were made with j/sub i/ = 8, 22, and 42 for approximately eight values of ..delta.. with an overall range of -20 to +24; a total of 69 cross sections were measured. Velocity selection is accomplished by a Doppler-based laser-selection technique combined with further numerical inversion methods. We achieve a measurable relative velocity range of approx. =0.5..-->..3 x 10/sup 5/ cm/s, corresponding to kinetic energies of 120 to 3500 K. In contrast to the few previous similar studies, our data show a dramatic and varied velocity dependence. We have observed a few cross sections which increase substantially with velocity, some which rise faster than v/sup -1//sub r/ at low velocity, some that fall like v/sup -2//sub r/ at high velocity, and numerous examples of peaks in endoergic cross sections near threshold. We have seen two distinct types of rotationally adiabatic reduction in certain cross sections: Vertical Bar..delta..Vertical Bar = 2 in Li(/sub 2/--Xe and j/sub i/ = 42, ..delta..< or approx. =-16, in all three systems, particularly in Li(/sub 2/--Ne.

• Research Organization: Research Laboratory of Electronics and Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
• OSTI ID: 6661332
• Journal Information: J. Chem. Phys.; (United States), Journal Name: J. Chem. Phys.; (United States) Vol. 81:3; ISSN JCPSA
• Country of Publication: United States
• Language: English

Related Subjects

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