The effect of particle motion character upon the rate of the resonant transfer of electronic excitation

Equations are derived for describing a classical system interacting arbitrarily with a quantum two-level system. The solutions for the case of two converging electron terms are analysed and applied to the problem of electronic excitation resonant transfer or resonant charge exchange. It is supposed that the classical motion of the particles (molecules) possesses a stochastic character and may be represented by the Fokker-Plank equation, when the interaction with the quantum degrees of freedom are absent. The model allows us to trace theoretically the change of excitation transfer kinetics when passing from gas to liquid and from liquid to the solid state. The general formula for one-, two- and three-dimensional relative motions are found and the three-dimensional case is discussed in detail.