Structure of a hard sphere fluid in ultrathin films between corrugated walls. A grand canonical Monte Carlo study

We have investigated a local structure of a hard sphere fluid adsorbed in a slit-like pore with corrugated wall using grand canonical Monte Carlo simu lations. The pore walls are modelled as an infinite set of regularly spaced rectilinear grooves of a few hard sphere diameter wide; the grooves are of stepwise shape along one of the axes of the pore plane and infinite in ano ther direction. The interactions between fluid particles and pore walls are assumed to be of a hard sphere type. We discuss the density profiles of fl uid particles in a wide and narrow region of the pore and analyze the densi ty distribution in the step region. We have obtained that the maximum fluid density is observed in the corner of a groove. It is shown that the pore w alls corrugation may yield a periodic variation of a fluid density parallel to the walls in the center of the pore. This effect depends on the width o f the pore and on, the depth of the grooves.