Charge Transfer and Vibrational Excitation in Molecule-Surface Collisions: Trajectorized Quantum Theory

Abstract

Vibrational excitation of diatomic molecules scattered from solid surfaces is considered. Emphasis is placed on a mechanism in which charge transfer between the molecule and surface creates a temporary molecular ion. A classical mechanics analysis of this effect has been presented previously. Here a mixed picture is offered in which the center-of-mass translational motion is treated classically with a trajectory approximation (TA) and the intramolecular vibrational motion quantum mechanically. A procedure for insuring energy conservation and microscopic reversibility in the TA is given. Both state-to-state T → V probabilities and mean energy transfer to the vibrational system are calculated for parameters which model N2 and I2 molecules and the results are considered in the light of the "exact" classical mechanics results.