Monte Carlo simulation of the crystal-melt interface of a Lennard-Jones substance

Abstract
The Monte Carlo method is used to study the properties of the interface between the (0001) face of a hexagonal-close-packed crystal of an idealized substance and its melt. The simulated system consists of 860 moveable ‘Lennard-Jones’ molecules, with boundary conditions periodic only in those directions parallel to the interface. The starting configuration is a computer-built dense hard-sphere model of the interface. After only a relatively short period of thermal equilibration, the potential energy remains essentially constant, and the system is considered as being in equilibrium. The principal results are (a) a density deficit at the interface and (b) a molecular mobility in the interfacial layer that is the same as that in the body of the liquid. Molecular mobility in the crystal layer adjacent to the interface is practically zero.