Generalized mean spherical approximation for a mixture of hard ions and hard dipoles against a charged hard wall

Abstract

A mixture of charged and dipolar (nonpolarizable) hard spheres near a uniformly charged hard wall of unit dielectric constant is considered. This is a simple model of an electrode-electrolyte interface. The Ornstein-Zernike equation for this system is completely solved for a generalized closure in which the bulk electrolyte and wall-electrolyte direct correlation functions are, for distances larger than the repulsive cores, written as a sum of some parametrized terms plus the corresponding pair potentials. Once the closure parameters are evaluated, the density, charge, polarization, and potential profiles are easily obtained. Comparison is made with the quadratic hypernetted chain and mean spherical approximations for the bulk correlation functions and with the mean spherical approximation for the charge, polarization, and potential profiles. © 1982 American Institute of Physics.