Vibrational–Translational Energy Transfer in the Near-Adiabatic Approximation

Abstract

Vibrational–translational energy transfer is examined in the near‐adiabatic (or perturbed stationary states) approximation. The results are classical, and the method used is related to that of Marcus [J. Chem. Phys. 49, 2617 (1968)]. The results are compared with those of the more usual (“static”) approximation and with the exact results. The PSS results were good at low energies at all mass ratios studied, unlike the static results. For certain mass ratios the static approximation fails badly, even at very low transition probabilities. For other mass ratios, the results are of comparable accuracy except at high energies where the static one is somewhat better. Reasons for the above behavior are discussed, and implications regarding existing infinite‐order distorted wave and semiclassical calculations are noted. The relation to a recent correction of the Jackson–Mott calculation is described.