SURFACE MELTING - A DENSITY-FUNCTIONAL APPROACH

A microscopic theory of surface melting is described and applied to Le nnard-Jones systems. Our approach is based on density functional theor y with the hard sphere fluid as a reference system. In particular we u se a weighted density approximation which yields an accurate Lennard-J ones bulk phase diagram. Within a practically free minimization of the functional, we find surface melting of a Lennard-Jones crystal for di fferent surface orientations. Furthermore the hard-sphere crystal-flui d interface and the hard-sphere crystal at a hard wall are explored wi th density functional theory. It is found that the crystal-fluid surfa ce tension of hard spheres is extremely small and that the hard wall p refers to be covered by a hard-sphere-solid at solid-liquid coexistenc e.