NONADIABATIC TRANSITIONS IN THE CONDENSED-PHASE - DERIVATION OF MULTICHANNEL FOKKER-PLANCK EQUATIONS FROM QUANTUM RELAXATION THEORY

A new formalism is proposed for the derivation of multichannel Fokker- Planck equations describing reactive processes in the condensed phase. It is based upon the method of quantum-classical reduction for the dy namical and relaxation parts of the general equation of quantum relaxa tion theory. In this way, the multilevel non-Markov Fokker-Planck and Smoluchovsky-type equations are obtained taking into account the non-a diabatic dynamics of the system. These equations include memory effect s with a generalization of the non-local relaxation kernel beyond the high-temperature approximation. The formulation of the balance equatio ns describing the kinetics of non-adiabatic reactions in polar solvent s is examined and the prospects of deriving corresponding rate express ions are discussed.