Theory and calculation of singlet excitation energy transfer in mixed molecular crystals

Abstract

A theoretical study of excitation energy transport among dipole–dipole interacting guests in mixed molecular crystals is carried out. To describe the temporal evolution of the excited state population, we derive a microscopic theory which treats an ensemble of dipole–dipole interacting guest molecules homogeneously distributed among two inequivalent sites of a host lattice. The theory is based on a generalized effective Hamiltonian accounting for intramolecular excited state depopulation and excitation energy transfer. The results are applied to the analysis of experimental data obtained from transient grating experiments in p-terphenyl:pentacene mixed molecular crystals.