On the theory of non-radiative transfer of electronic excitation

Abstract
In a previous paper, the Dexter-Förster theory was reformulated so that it can be used to discuss explicitly effects of temperature, isotope substitution and the energy gap between the excited donor and the ground state acceptor on the rate of energy transfer. In this paper, the equivalence of the two formulations is shown and some new results obtained from the reformulation are presented. The inelastic collision cross-sections for singlet-singlet, triplet-singlet, and triplet-triplet transfers have been obtained by using the first Born approximation. The relation between the quenching constant and the quenching cross-section is discussed. It is shown that for singlet-singlet and triplet-singlet transfers in the gas phase, both Coulomb and exchange interactions are important. The energy transfer probability in the solid phase and the quenching constants in the collisional energy transfer are compared. Some experimental results of the energy transfer measurements in the gas phase are discussed.