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-s olvent interactions is then solved using a one-parameter family of tri al functions for the electronic density profile, and a systematic inve stigation of the metal-solvent bond length (chi(1)) and its dependence on electrode charge density (sigma(M)) is presented. The crucial role played by chi(1) in double-layer analysis is also pointed out using t he variation of inner layer capacitance with sigma(M) at the Hg/NaF in terface. The model is then used to analyze the effect of temperature, bulk electron density of the metal, and electron-ion coupling terms us ing Ashcroft pseudopotential on the capacitance-potential plots. The p osition of the image plane and its variation with electric field, elec tron density of metals, etc., have also been outlined. The influence o f external field on work function changes pertaining to solvent adsorp tion at electrochemical interfaces is discussed.