Structure of a hard-sphere fluid in hard wedges

We investigate local structural properties of a hard-sphere fluid exposed to periodic arrays of parallel hard wedges by means of grand canonical ensemble Monte Carlo simulations. The corrugated substrate is characterized by the dihedral angle γ of the grooves, the angle 2π-γ of the tips, and the lateral periodicity length sₓ in the x direction; γ is varied over the range π/2<~γ<~π including a planar wall (γ=π) as a special case. In the second lateral direction y periodic boundary conditions are used, whereas confinement in the normal direction z is accomplished by two opposite substrates sufficiently far apart. We analyze the ordering of the fluid within the grooves and at the tips, respectively, in terms of the number density ρ(x,z;γ). The crossover between these two regions exhibits pronounced density oscillations. From the density distribution we extract the excess coverage Γ(γ), which up to now has been known only for γ=π; in this special case we find excellent agreement with previous work. Γ(γ) is composed of surface and line contribution whose relative magnitude permits us to quantify corrugation effects vs planar confinement.