Theoretical Calculations of Excitation Energy Transfer

Abstract

A transition–density–fragment interaction combined with a transfer integral (TDFI-TI) method is explained. The basis of the TDFI-TI method is to describe the elements of the Hamiltonian matrix, and it gives quantitative descriptions of the electronic coupling energies and the absorption spectra. The TDFI-TI method allows us to perform the decomposition analysis, which provides the components of the electronic coupling energy. Moreover, the TDFI-TI method can reduce the computational costs, compared with the full quantum-mechanical (QM) method. The TDFI-TI approach is useful for analyzing and understanding the mechanism of excitation energy transfer and crystallochromy.