Electronic energy transfer in an impurity band

In this paper we explore the dynamics of triplet electronic energy transfer in an impurity band of a substitutionally-disordered material. The general characteristics of the solutions of the master equation in the strong scattering regime have been studied, leading to a generalized diffusion equation that contains a memory term, which results in a time-dependent diffusion coefficient. Approximate results for the average density of excitation were derived within the framework of the pair-approximation, resulting in explicit expressions for the time-resolved spectral diffusion, the mean-square displacement, as well as the time-dependent diffusion coefficient for electronic transfer processes induced by exchange interactions.