A MONTE-CARLO STUDY OF INTERMOLECULAR ELECTROSTATIC INTERACTIONS AT THE ELECTRODE ELECTROLYTE INTERFACE

A standard Metropolis Monte Carlo method has been adopted to simulate properties of solvent molecules occurring at the inner part of the charged electrode/electrolye solution interface: the mean dipole moment, the differential dipole polarizability and the mean energy of intermolecular interactions. Molecules have been distributed over the electrode surface into a hexagonal or square lattice. Considerations have been restricted to the orientation effect. In the calculations, the energy of intermolecular interactions of the dipole-dipole type and interactions between the electrode surface charge and the molecular dipole moment have been taken into account. It has been observed that the increase in the energy of the intermolecular interactions caused by the increase in the permanent dipole moment of the solvent molecules, mu, leads to: (i) a decrease in the reducee mean dipole moment, <mu>/mu, at a given electrode surface charge, which is contrary to the results obtained from the Langevin function, (ii) an increase in the width of the dipole polarizability-surface charge curves (in some cases the transformation of a polarizability maximum into a plateau with small maxima on both sites takes place), and (iii) an almost steady dipole polarizability at the uncharged electrode. The mean energy of the intermolecular interactions is negative for small electrode charges and positive for higher values.