New theoretical description of electrified interfaces

Abstract

Starting from a Landau–Ginzburg-like Hamiltonian we have analysed an extension of the Gouy–Chapman theory. It contains three phenomenological parameters describing the overall effect of interionic correlations. We show that the expression for the differential capacitance takes a simple and very suggestive form. We use a numerical method to calculate ionic profiles and diffuse layer capacitance. Depending on the parameters, a variety of behaviours for the charge dependence of capacitance can be generated. We discuss the consequences of our model for the interpretation of experimental data based on the Parsons–Zobel plot.