MOLECULAR DYNAMICS STUDY OF STRUCTURAL INSTABILITY OF TWO-DIMENSIONAL LATTICES.

Structural transition of a two-dimensional square lattice with Lennard-Jones interaction to a triangular lattice has been studied by a molecular dynamics simulation technique which allows the system to vary in size and shape. The results are consistent with lattice dynamics analysis, and furthermore provide sufficient details to determine the mechanism of transition. The same technique was then used to simulate the onset of melting at constant pressure. It is shown that thermodynamic properties and structural behavior give a consistent picture of the evolution of this thermal instability.