Coulomb Green's functions at diffuse interfaces

Abstract

The effect of the spatial variation of the dielectric constant across the air/water and metal/water interfaces on the energy of an ion in those regions is considered. This extends the recent work of Clay, Goel and Buff in two ways. Firstly, a single dielectric profile of finite range is constructed, for which analytic calculation of image potentials is possible. These solutions have a much simpler mathematical structure than those obtained by Clay et al. Secondly, the effect of the adjacent diffuse layer on image potentials at the metal/water interface is investigated. In all cases the answers are consistent with previous multiple imaging calculations on discontinuous interfaces, without the divergences at boundaries predicted by these models.