Electron Transfer at the Interface of Two Immiscible Liquids

In this section we shall discuss the question of the dependence of the electron transfer rate in a two-phase system on the reactants position relative to the interface. In the case of the electron transfer reaction in the one-phase system 

Here feo is the pre-exponential factor proportional to the effective frequency coq of a vibrational subsystem and to the transmission coefficient of the reaction x, AFq is the reaction free energy, Vi is the free energy of approaching of reactants from the infinity to the reaction configuration corresponding to some effective distance R between the reactants, Vf is the free energy of separating the reaction products and Eg is determined by Eq. (12). 

The approximate calculation of the solvent reorganization energy for the charge transfer between spherical reactants was carried out by Marcus [2]. Under the assumption that the distance between the centres of reactants R is much larger than their radii a and b and that the reactants can be described by non-polarizable spheres with the charges strictly and uniformly distributed over their surfaces, the expression for Eg obtained in Ref. [2] has the form 

In some papers [27-29] an improved expression for Eg was obtained, which takes into account the effect of mutual polarizability of reactants and the effect of a finite size of reactants in calculating the integral in Eq. (12). Both the above effects give rise to additional terms of the order of a /R and b /R in the geometric factor in Eq, (45). Energies Vi and Vf in Eq. (44) can be expressed as 

Now we shall consider the charge transfer process near the interface between the two immiscible liquids which have static dielectric constants and 82 and optical dielectric constants Sqi and 8q2- We shall distinguish three basic cases of the reactants positioning relative to the interface L Both reactants are placed in the medium with static dielectric constant (Fig. 7a). II. One of the reactants for 

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