Monte Carlo simulation of the crystal to plastic crystal transition in carbon tetrachloride

The Metropolis Monte Carlo method in the isothermal isobaric ensemble has been extended to enable study of phase transitions in molecular systems, and used to investigate the transition from the crystalline to the orientationally disordered (plastic-crystalline) phase of carbon tetrachloride. The problem of rotation of the cell has been examined. The radial distribution functions, displays of the molecular arrangements in the crystal, and the cosine of the angle between the molecular C 3 axis and the crystallographic [101] direction show clear evidence for the existence of a transition around the temperature expected from experiments.