Semiclassical collision theory within the Feynman path-integral formalism. II. Application to vibrational excitation

A multichannel semiclassical collision theory, based on Feynman's path-integral formulation of quantum mechanics and discussed previously by us, is applied to the problem of vibrational excitation during collinear atom-diatom collisions. The diatom is treated as a harmonic oscillator and the atom-diatom interaction is an exponential repulsion. The semiclassical results are compared with the exact quantum-mechanical calculation of Secrest and Johnson and with the classical S-matrix theory of Miller and Marcus. It is found that the present theory is not as generally useful as the theory of Miller and Marcus.