Phase diagram for the inverse sixth power potential system from molecular dynamics computer simulation

Abstract
The phase diagram for the inverse sixth power potential is calculated via molecular dynamics computer simulation. Free energies are evaluated by thermodynamic integration. The crystal phase at freezing is determined to be body centred cubic (bcc). The region of stability of this phase is, however, relatively narrow and the system undergoes a bcc-fcc transition at densities only slightly higher than the freezing point. Finite size effects in the simulation are examined. A new extension of the lattice-coupling method for calculating crystal free energies is presented, in order to avoid a singularity in the scheme.