Electron tunneling in solid phase redox reactions. Experimental values of parameters characterizing the rate of tunneling and theoretical models for long range electron transfer

The problem of the quantitative analysis of the kinetic data for the tunnel electron transfer reactions in solids is discussed. Various procedures are considered with the help of which one can determine from the experimental data the parameters v and a in the equation w = v exp (?2r/a) describing the dependence of the electron tunneling frequency w on the distance r between the reacting particles. For numerous tunnel reactions studied in the literature these parameters are calculated and their values are analyzed in terms of theoretical models of electron tunneling. The physical background of these models is discussed in detail to make it more understandable for experimentalists. The limits of applications for these models are discussed. A novel model for nuclear motion in the process of electron tunneling is proposed to account for the unusually high values of the frequency factor found for some of the reactions.