Nonadiabatic semiclassical scattering. I. Analysis of generalized surface hopping procedures

Abstract

A formal analysis of generalized, semiclassical surface‐hopping approaches to nonadiabatic scattering is undertaken. Expressions are obtained for the transition and reflection amplitudes for intersurface jumps. In problems involving two adiabatic electronic states, it is found that only the component of the heavy particle momentum which is parallel to the nonadiabatic interaction vector η=〈χ^el₁‖∇χ^el₂〉, is adjusted so as to conserve energy in the transition between adiabatic energy surfaces, given certain reasonable assumptions concerning the form of the wave function. This is the first time a prescription for the post‐transition momentum has been presented in a less than ad hoc fashion.