Analysis of the diffuse layer potential drop in the limit of small fields on the basis of a generalized mean spherical approximation

Analytical expressions have been derived for the functions Ξo and Ho which arise in the description of the diffuse double layer using a generalized mean spherical approximation (GMSA). The analytical expressions are shown to provide a very good alternate method to estimate Ξo and Ho which were calculated on the basis of numerical evaluation of integrals in previous work. They are valid in the limit of small electrical fields, a region in which the GMSA itself is valid. The GMSA results are compared to data obtained in Monte Carlo simulations carried out at the primitive level as a function of ion size and concentration for a 1–1 electrolyte.