LAUSR

Abstract We consider a closed two-state model that can represent reversible reaction–diffusion systems. The dynamics of the reacting species are governed by coupled Smoluchowski equations. The potential curves are assumed to be flat, and the probability distributions of the species are assumed to be Gaussian functions for the initial time. Two cases are considered: (a) case when both states are initially populated, (b) a case when all the initial population is excited. The obtained time-dependent population probabilities for case (a) explain the effect of molecular parameters on the concentration profiles for a reversible reaction. The results for case (b) give the transient effect of viscosity, excitation, and molecular parameters on the electronic relaxation process. The coupled equations are considered unsolvable in the literature, and the presented solution of a simple model gives insight into the chemical processes.