Hard sphere mixtures near a hard wall

Hard spheres with ratios of diameters of 3:5 and 1:3 and at various densities are studied by means of grand canonical ensemble (GCE) simulations, first- and second-order Percus—Yevick theory, scaled particle theory (SPT) and density functional theory (DFT). Generally, but not always, the density profiles of the first-order Percus—Yevick (PY1) theory results are smaller at contact than the GCE simulation results. The second-order Percus—Yevick (PY2) and DFT results are in much better agreement with the simulations. PY2 theory seems to be more accurate than DFT but is much more demanding computationally.