STRUCTURE OF A HARD-SPHERE FLUID IN HARD WEDGES

We investigate local structural properties of a hard-sphere fluid expo sed to periodic arrays of parallel hard wedges by means of grand canon ical ensemble Monte Carlo simulations. The corrugated substrate is cha racterized by the dihedral angle gamma of the grooves, the angle 2 pi - gamma of the tips, and the lateral periodicity length s(x) in the x direction; gamma is varied over the range pi/2 less than or equal to g amma less than or equal to pi including a planar wall (gamma=pi) as a special case. In the second lateral direction y periodic boundary cond itions are used, whereas confinement in the normal direction z is acco mplished by two opposite substrates sufficiently far apart. We analyze the ordering of the fluid within the grooves and at the tips, respect ively, in terms of the number density rho(x,z;gamma). The crossover be tween these two regions exhibits pronounced density oscillations. From the density distribution we extract the excess coverage Gamma(gamma), which up to now has been known only for gamma = pi; in this special c ase we find excellent agreement with previous work. Gamma(gamma) is co mposed of surface and line contribution whose relative magnitude permi ts us to quantify corrugation effects vs planar confinement.