Theory of electrified interfaces: A combined analysis using the density functional approach and Bethe approximation

A new analysis of the metal/electrolyte interface using jellium model for metal surfaces and Bethe approximation for dipolar interactions is carried out. The total surface energy taking into account the metal-solvent interactions is then solved using a one-parameter family of trial functions for the electronic density profile, and a systematic investigation of the metal-solvent bond length (X1) and its dependence on electrode charge density (OM) is presented. The crucial role played by x1 in double-layer analysis is also pointed out using the variation of inner layer capacitance with OM at the Hg/NaF interface. The model is then used to analyze the effect of temperature, bulk electron density of the metal, and electron-ion coupling terms using Ashcroft pseudopotential on the capacitance-potential plots. The position of the image plane and its variation with electric field, electron density of metals, etc., have also been outlined. The influence of external field on work function changes pertaining to solvent adsorption at electrochemical interfaces is discussed.