On Theoretical Treatments of Electronic Excitation Energy Transfer

In this paper, we review the generalized Forster‐Dexter theory to treat photoinduced electronic energy transfer for a system in dense media and for an isolated system (i.e., a system in the collision‐free condition). Instead of expressing the rate of energy transfer in terms of spectral overlap, the expression of the energy‐transfer rate constant is obtained by evaluating a Fourier integral involved in the energy transfer rate constant using the saddle‐point method. In this way, the energy‐gap dependence, and the effect of temperature and the isotope effect on the energy transfer can be easily studied. The effect of bridge groups connecting between donor and acceptor chromophores on the intramolecular energy transfer is also studied.