K+CH3I→KI+CH3 revisited: the total reaction cross section and its energy and orientation dependence. A case study of an intermolecular electron transfer

Abstract

The dynamics of the K+CH₃I reaction is discussed with special reference to two factors that govern the electron transfer. One is that at higher collision velocity the behavior need not be adiabatic so that there can be a finite probability for the electron not to transfer, resulting in no reaction. The other is the marked increase of the electron affinity of CH₃I with its bond extension. The electron transfer can therefore take place at much larger separation of the reactants if CH₃I is stretched. The barrier to reaction is then much lower. These observations are used to discuss the stereodynamics of the reaction. Several open problems are identified.