Theory of monolayer physical adsorption. III. Density functional theory of two-dimensional nonuniform fluids and theory of freezing

Density functional theory is applied to the description of submonolayer physical adsorption of spherically symmetric molecules on an exposed simple crystal face of an inert solid. To support calculations of the thermodynamic functions characterizing adsorption, a method of computation of the one- and two-particle distribution functions of a nonuniform adsorbed fluid is presented. With some knowledge of the structural information for the nonuniform fluid we next describe a theory of freezing of submonolayer films. Theoretical arguments are supplemented by numerical calculations of the freezing of hard spheres on a periodic solid surface. The results obtained are compared with experiments and computer simulations for rare gases on graphite.