Structure of a inhomogeneous fluid mixture: A new weighted density-functional theory within a perturbative approach

摘要

A simple density-functional approach is developed for an inhomogeneous fluid mixture where the functional Taylor expansion of the perturbative approach has been used along with a nonperturbative weighted density prescription. The functional Taylor expansion of the one-particle direct correlation function (DCF) of the inhomogeneous fluid mixture is truncated at second order in density inhomogeneity and the effect of various higher-order terms is taken into account by evaluating the third-order DCF at an weighted density obtained by using a suitable weight function which obeys certain conditions in the homogeneous limit. The proposed approach uses the two-particle DCFs of the corresponding uniform fluid mixture and their various density derivatives as inputs. The calculated numerical results for the density and concentration profiles of hard sphere mixtures near hard walls for different set of bulk parameters are shown to be in very good agreement with the available simulation data.