Incoherent Energy Transfer
In this chapter, we study the transfer of energy from an excited donor molecule to an acceptor molecule. We discuss different mechanisms involving electron exchange, simultaneous radiationless deexcitation and excitation or photon emission followed by reabsorption. Using a simplified MO model, we calculate the coupling matrix element of the Coulomb interaction in dipole approximation and evaluate the famous Förster expression for the transition rate. Within the Condon approximation, the overlap of donor emission and acceptor absorption spectra becomes an essential factor. Finally, we comment on energy transfer in the triplet state.