The double layer at the interface between a simple metal and an aqueous solution

Abstract

We consider the interface between a simple metal, modelled as jellium, and an aqueous solution. In order to estimate the effect of the water on the distribution of electrons in jellium, we perform molecular dynamics simulations using the central force model for water. From these simulations, and from an effective pseudopotential for the electron-water interaction, we obtain the average interaction potential experienced by the metal electrons. Explicit model calculations for a mercury electrode predict a significant lowering of the electronic work function in water. The position of the effective image plane is also brought closer to the jellium edge, which results in better values for the double layer capacity.