Classical S-matrix calculations of vibrational transition probabilities in the Li+-H2system

Abstract

Describes the first application of the classical S-matrix method to a system for which both experimental transition probabilities and suitable potential energy surfaces exist. Special emphasis is given to the effects on the calculated transition probabilities of vibrational anharmonicity of the hydrogen molecule, and the particular form of the potential energy surface on which the collision takes place. The calculated results are in good agreement with the major features of the experimental data, suggesting that classical S-matrix theory will allow the computation of macroscopic properties such as vibrational relaxation times for gas mixtures with an accuracy limited only by our knowledge of suitable interaction potentials. Although there are discrepancies between the present calculations and the details of the experimental behaviour, these are attributed to uncertainties in the form of the interaction potential energy surfaces at small ion-diatom separations, and the neglect of simultaneous rotational excitation.