A comparison of exact classical and quantum mechanical calculations of vibrational energy transfer

Journal Article · Wed Dec 01 04:00:00 EST 1976 · J. Chem. Phys.; (United States)

DOI:https://doi.org/10.1063/1.432971· OSTI ID:7331999

Gordon, R J

Exact classical and quantal calculations of vibrational energy transfer were compared to determine the conditions under which classical mechanics is reliable. A detailed study of collinear collisions between an atom and a harmonic oscillator with a repulsive exponential interaction showed that the average classical and quantal energy transfer agree within a few percent, if the translational energy exceeds the vibrational spacing, and if the average energy transfer does not change sign as the collision energy is varied slightly. Additional collinear calculations with (I) a Morse oscillator and an exponential interaction and (II) a harmonic oscillator with a Lennard-Jones interaction confirmed this result, except for the case of a deep potential well. In this case sticky collisions can occur, and the agreement is poorer. For collinear collisions of two harmonic oscillators with a repulsive exponential interaction, the agreement for T..-->..V energy transfer was poorer than in the atom--diatom case. Good agreement was obtained for V..-->..V transfer, with both classical and quantum calculations favoring resonant collisions.

• Research Organization: Department of Chemistry, University of Illinois at Chicago Circle, Chicago, Illinois 60680
• OSTI ID: 7331999
• Journal Information: J. Chem. Phys.; (United States), Journal Name: J. Chem. Phys.; (United States) Vol. 65:11; 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
ENERGY LEVELS
ENERGY TRANSFER
EXCITED STATES
HARMONIC OSCILLATORS
LENNARD-JONES POTENTIAL
MOLECULE COLLISIONS
MORSE POTENTIAL
VIBRATIONAL STATES