DYNAMICS OF CHARGE-TRANSFER CHEMICAL-REACTIONS IN A POLAR MEDIUM WITHIN THE SCOPE OF THE BORN-KIRKWOOD-ONSAGER MODEL

A theoretical scheme designed for the dynamical treatment of charge transfer chemical reactions in polar solvents within the scope of the Born-Kirkwood-Onsager model (BKO) is proposed. According to the BKO model a medium is considered as a uniform continuum where a cavity containing a chemical subsystem is cut out. The continuum representation of the medium implies a complex function for the dielectric permittivity epsilon(omega), being the only specific property of the medium. An inertial polarization field PHI-in is used as a medium variable. A procedure of separation of the noninertial polarization is developed using the BKO model. A free energy functional is introduced which may be considered as an energy surface of the united "chemical subsystem + medium" system both for equilibrium and non-equilibrium realizations of the polarization field. The equation determining equilibrium realizations of the inertial field PHI-in in the nonlinear case, when the charge distribution of the chemical subsystem depends on the medium polarization, is obtained on the basis of the variational principle. Starting from this equation a dynamical equation describing the temporal evolution of the charge transfer process is derived.