STRUCTURE OF HARD-SPHERES IN CONTACT WITH A SPHERICAL WALL

We study the structure of hard-sphere fluids in a spherical cavity with Monte Carlo (MC) simulation, the density-functional hypernetted-chain approximation, and the linear theory discussed by Henderson, Abraham, and Barker. The density at the wall as a function of the sphere radius is determined. We found that the density profile consists of a sum of a surface term localized at the interface and a damped oscillation. A qualitative picture of this in terms of the linear theory is proposed. Even though the linear theory produces a density at the wall lower than the MC results for flat walls, it provides for a surface density that is higher than the MC result for spherical walls of 10 atomic diameters. Furthermore, this density increases as the radius is decreased in the linear theory, opposite to the trend seen in the MC simulations. A reason for this is proposed. The nonlinear theory does not seem to work very well, consistent with previous results for a flat wall.