Relaxation processes and chemical kinetics

Abstract

The role of relaxation processes in determining the rates of activated events has long been a point of discussion in chemical physics. In this paper, we re-examine this issue. We idealize the problem as the classical motion of a particle in a one-dimensional potential coupled to a heat bath. This situation is described by a kinetic equation with a ’’collision operator’’ gℓc. An expansion in powers of the damping constant g is developed. This expansion is not limited to the case of high activation barriers. We compare results for various choices of the collision operator and provide a new derivation of Slater’s new rate theory. A Padé approximant approach unifies our low g results with those in the high g, i.e., diffusive, regime.