INTERMOLECULAR FORCES AND PHASE-TRANSITIONS IN SOLID C(60)

We use a simple intermolecular potential to describe a large number of properties of solid C60. Minimizing their free energies we establish an equation of state for both phases, and calculate the phase diagram, discontinuities at the phase transition, and, in general, static, dynamic, and thermodynamic properties as a function of temperature and pressure, in good overall agreement with experiment. We find that in the lower temperature phase several secondary orientational energy minima appear, and that therefore the simple two-level picture for the residual orientational disorder must be revised.