A Singlet-RISM theory for solid/liquid interfaces part I: Uncharged walls

We present a novel integral equation method for the calculation of fluid structure in the vicinity of a plane impenetrable wall. The theory is based on the well-known RISM equation and is capable of dealing with arbitrary interaction site model (ISM) fluids at a solid/liquid interface. In conjunction with several closure approximations, the equations are solved numerically and wall-fluid site density distributions as well as charge density, field, and potential profiles are calculated for pure water and aqueous electrolyte solutions with varying, concentrations adjacent to an uncharged soft wall. The results show reasonable agreement with corresponding computer simulation data.