Hard spheres at a planar hard wall: Simulations and density functional theory

Hard spheres are a central and important model reference system for both homogeneous and inhomogeneous fluid systems. In this paper we present new high-precision molecular-dynamics computer simulations for a hard sphere fluid at a planar hard wall. For this system we present benchmark data for the density profile rho(z) at various bulk densities, the wall surface free energy gamma, the excess adsorption Gamma, and the excess volume vex, which is closely related to Gamma. We compare all benchmark quantities with predictions from state-of-the-art classical density functional theory calculations within the framework of fundamental measure theory. While we find overall good agreement between computer simulations and theory, significant deviations appear at sufficiently high bulk densities.