The BGY3dM model for the approximation of solvent densities.

We present a new approach for the approximation of solvent densities around solutes of arbitrary shape. Our model represents a three-dimensional (3d) Born-Green-Yvon (BGY) equation for an arbitrary solute immersed into a molecular (M) solvent, the BGY3dM model. It comprises the famous Kirkwood approximation as closure relation. The molecules of the solvent are modeled as rigid bodies by taking the limit of an infinite restoring force for the intramolecular interactions. Furthermore, short-range potentials as well as the long-range Coulomb interaction are taken into account. The resulting integro-differential equations are efficiently solved by a Picard iteration and a solution of the linearized equations using Fourier transformations. We compare the results obtained from the presented BGY3dM method with results obtained by extensive molecular dynamics simulations for a HCl-like model solvent. Furthermore, we apply the method to carbon disulfide as solvent. The overall performance of the method is promising.