Abstract

In this paper we present a study of a model in which there is energy transfer as well as a special site where an irreversible reaction takes place. This model has an arbitrary ratio of homogeneous broadening versus site interaction energy. This allows us to study the crossover from hopping dynamics to exciton dynamics. We show that for the survival time the hopping (Forster) approximation gives a surprisingly accurate final result even when the energy transfer is excitonic. Fluorescence depolarization however is a sensitive probe for the nature of the energy transfer. We study the number of coherent molecules by considering a generalization of the inverse participation ratio. For LH1 we estimate that the excitation is on the average delocalized over 4.4 pigments.

© 1996 IEEE