Energy Transfer between Impurity Molecules of a Crystal in the Presence of Relaxation

The time dependence of the probability W( t ) of excitation energy transfer from the donor to the acceptor for various values of resonance interaction energy ( ħ L ), donor excitation energy relaxation time (γ −1 ), and the relaxation time (λ −1 ) of the vibrational part of acceptor excitation energy is found using the method of density matrix. It is shown that W (∞) = \documentclass{article}\pagestyle{empty}\begin{document}$ \frac{{\lambda \alpha ^2 }}{{(\lambda + \gamma)(1 + \alpha ^2)}}{\rm where } \alpha {\rm = }\frac{{{\rm 2|}L{\rm |}}}{{\sqrt {\gamma \lambda } }} $\end{document} . Thus, W (∞) is proportional to the square of resonance interaction energy at α ⪅ 0.2. However, W (∞) is approximately proportional to α with the values of α satisfying the inequality 0.2 ⪅ α ⪅ 1.7.