Distribution functions of a heteronuclear hard dumbbell at a hard wall. Pure fluid and mixtures with hard spheres

Distribution functions (angle-averaged site/wall correlation functions) in the inhomogeneous systems of a heteronuclear hard dumbbell (of the site diameter ratio [image omitted] and [image omitted]) were studied theoretically by applying a simple method to determine the background (cavity) correlation function from the residual chemical potentials of the hard dumbbell, hard wall and the corresponding combined body. Pure fluid and approximately equimolar mixtures of dumbbells with hard spheres were considered at several densities. Theoretical distribution functions for the most important site-wall distances were calculated and compared with simulation data; fair agreement was found. Advantage of the proposed method is its simplicity (the residual chemical potential depends, besides the packing fraction, only on the geometric characteristics of the hard body-its volume, surface area and mean radius); the method provides quick information on the density profiles in different inhomogeneous systems.