A theoretical study of transport and trapping of electronic excitations in a twohyphen;component disordered system is carried out. The results are applicable to energy transport in solutions containing randomly distributed donor and trap solute species or lattices with randomly distributed donor and trap impurities. The diagrammatic expansion of the Green function, developed by Gochanour, Andersen, and Fayer to study excitedhyphen;state energy transport in a onehyphen;component system is applied to the trapping problem. The following quantities are calculated from the Green function: the timehyphen;dependent probabilities that an excitation is in the donor or in the trap ensembles, the generalized diffusion coefficient, and the meanhyphen;squared displacement of an excitation. For Fouml;rster transfer, transport properties are shown to depend on the ratio of the Fouml;rster interaction lengthsRDT0andRDD0as well as on the reduced concentrations of donors and traps lsqb;CD= 4/3pgr;(RDD0)3rgr;D,CT= 4/3pgr; (RDT0)3rgr;Trsqb;. The tranport of excitations is found to be nondiffusive. A comparison to other theoretical treatments is presented.
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