ELECTRONIC EXCITATION TRANSFER IN CLUSTERED CHROMOPHORE SYSTEMS - CALCULATION OF TIME-RESOLVED OBSERVABLES FOR INTERCLUSTER TRANSFER

A theoretical description is given for electronic excitation transport among interacting clusters of chromophores. Each cluster is a finite volume system with a limited number of chromophores. At high cluster concentration, intercluster transfer will become significant. The theory is based on a first-order cumulant approximation of the solution to the transport master equation. G(s)(t) the probability of finding the excitation on the initially excited chromophore is calculated. The problem is first solved for two clusters at fixed separations. This result is extended to many clusters and then to the thermodynamic limit of an infinite number of clusters in an infinite volume. An example calculation is performed of excitation transport among chromophores on the surfaces of interacting micelles. For realistic parameters characterizing the system octadecylrhodamine B (chromophores) in Triton X-100 micelles, it is found that intermicelle excitation transfer can compete with intramicelle transfer. For an isolated micelle-chromophore system (chromophores on the surface of a sphere), a new time domain expression for G(s)(t) is obtained.