The transfer of atoms, ions and molecular groups in solution. Part 3.—Monte Carlo methods for the evaluation of rate constants

Abstract

This paper describes the use of Monte Carlo methods in the evaluation of certain averages which are encountered in the theory of reaction rates. In particular, the transition-state theory is outlined and the Monte Carlo method is introduced at appropriate points. The method of Monte Carlo averaging is illustrated by considering the reactive inversion of a bent A—B—A molecule in a two-dimensional solution of disc-like solvent. The activation energy for the transformation to a linear transition state is determined. Throughout the calculation it is possible to keep a record of the average adiabaticity of the reaction. The analysis used for this simple model can be extended to more realistic systems.