MONTE-CARLO SIMULATION STUDY ON THE STRUCTURE AND REACTION AT METAL-ELECTROLYTE INTERFACE

Monte Carlo simulation calculations were made for investigating the st ructure and the mechanism of the electron transfer reactions at the me tal-electrolyte interface. All the particles are assumed to be spheric al with the same radii and the metal was treated as a source of the mi rror image force. We obtained a result that many electrolyte ions are directly adsorbed to the metal surface in the presence and absence of the external field, indicating that the structure of the interface is non-uniform and a strong alternating local field is produced. Free ene rgy surfaces for the electron transfer reaction are calculated using t he simulation data. We found that the distance fluctuation of a reacta nt from the metal surface makes significant contribution to the free e nergy surfaces as well as the orientational and positional fluctuation s of solvent and electrolyte ions do, and that the distribution of the se fluctuations deviate greatly from the Gaussian, bringing about larg e nonlinear response effects in the relation between the activation fr ee energy and energy gap of the reaction.