On the perturbative analysis of the dynamics of reactive collisions

Abstract

This paper explores the application of quantum mechanical perturbation theory to the determination of reactive transition probabilities. The very simple problem of particle reflection and transmission at a one-dimensional potential barrier is examined over a wide range of energies and for alternate perturbative schemes. The first scheme is conventional; the second is based on a quasi-adiabatic (QA) description of the dynamics. We find that for a choice of model parameter values, loosely based on the H+H2 system, the first (conventional) scheme provides quantitatively accurate results. However, at higher system masses, the first scheme results are in only moderate agreement with exact results and are highly sensitive to the variation of distortion potential parameters. For the high system mass case, the QA results are in much better agreement with the exact results. However, the QA results are also highly sensitive to the variation of QA potential parameters. We discuss finally a number of avenues for further investigation.