Modification of the Image Potential for the Interfacial Zone with Varying Dielectric Constant

Abstract

The overall nature of the image potential term is studied classically for a flat interfacial zone, where the dielectric constant changes from ε₁ to ε₂ as a function of distance normal to the interface. A perturbation theoretic approach is taken, where γ=(ε₁−ε₂)⁄(ε₁+ε₂) is shown to be a relevant expansion parameter. Results useful in treating the diffusive interface are given up to second order in γ.