Abstract: Based on the continuum medium theory and the basic principles of thermodynamics we used an extra electric field Eex to change the non-equilibrium salvation state 2[Enon2, Dnon2] to a constrained equilibrium state [E*2, D*2]. A novel expression of solvent reorganization energy was deduced. Furthermore, by adopting the sphere-interface approximation we deduced the formula for the solvent reorganization energy of the electron transfer reaction occurring at the interface of the conductor and the solvent. Compared to the traditional Marcus model our result was scaled by a factor of (εs-εop)/(εop(εs-1)) which is about 0.5 in a polar solvent. C343(Coumarin 343)-TiO2 was used as an example and the analytical results using our model were discussed with respect to experimental measurements.

Key words: Non-equilibriumsolvation; Constrained equilibrium; Solvent reorganization energy; Interface