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Title: Vibrational energy transfer in atom--polyatomic collisions: The role of intramolecular dynamics in Li/sup +//CO/sub 2/ and Li/sup +//N/sub 2/O

Journal Article · · J. Chem. Phys.; (United States)
OSTI ID:5576837

Using a quantal many-body theory of hyperthermal atom--polyatomic collisions, we present a detailed study of the role of intramolecular dynamics in vibrational energy transfer. In this approach, differential vibrational cross sections are given by time-correlation functions (TCFs) of the motions of the target atoms. Slow rotations of polyatomic molecules are decoupled from vibrations, and we concentrate on vibrational energy transfer. The dependence of the TCFs on collision energy, scattering angle, and changes in vibrational quantum numbers is examined in detail for a general polyatomic, and it is shown how each target atom contributes to vibrational energy transfer. For the systems Li/sup +//CO/sub 2/ and Li/sup +//N/sub 2/O, we present vibrational differential cross sections calculated with new multicenter short-range potentials obtained from the uniform electron-gas model. Comparison of theoretical results with experimental measurements of the Li/sup +//CO/sub 2/ system shows good agreement for several collision energies and scattering angles. Furthermore, we show how the structure of the vibrational cross section is related to the atomic parameters of the target and to the relative sizes of the repulsive cores of the intermolecular potential.

Research Organization:
Departments of Chemistry and Physics, University of Florida, Gainesville, Florida 32611
OSTI ID:
5576837
Journal Information:
J. Chem. Phys.; (United States), Vol. 78:6
Country of Publication:
United States
Language:
English