The surface diffusion coefficient for an arbitrarily curved fluid–fluid interface. (II). Coefficient for plane-parallel diffusion

In this paper we developed an expression for the coefficient for plane-parallel diffusion for an arbitrarily curved fluid–fluid interface. The expression is valid for ordinary diffusion in binary mixtures, with isotropic bulk phases and an interfacial region that is isotropic in the plane parallel to the dividing surface. The expression can be used in MD simulations and calculates the plane-parallel diffusion coefficient as a function of the perpendicular distance to the dividing surface. From this profile and the total density and concentration profiles in the interfacial region, the surface diffusion coefficient can be calculated.