Density functional theory of inhomogeneous fluid mixture based on bridge function

A simple density functional theory is proposed for an inhomogeneous fluid mixture by approximating its one-particle correlation function in terms of the second-order direct correlation functions and the bridge function of the corresponding homogeneous system. The theory is applied to predict the structure of a binary hard sphere mixture as well as Lennard-Jones fluid mixture near a hard wall, and the calculated density profiles for both the components are shown to agree quite well with the corresponding computer simulation results for both the systems. This theory for an inhomogeneous fluid mixture is further applied to homogeneous hard sphere mixture as well as Lennard-Jones fluid mixture and the calculated radial distribution functions are found to compare quite well with the same obtained through integral equation theory of fluid mixture.