The freezing transition in SF6

This work confirms the result of the Bartell group (K.E. Kinney, S. Xu, L.S . Bartell, J. Phys. Chem. 100 (1996) 6935) that the molecular liquid cluste r of SF6, simulated by molecular dynamics, transforms to the plastic phase when cooled sufficiently slowly. This also occurs in the bulk at and below 140 K. Attempts are made to instigate or accelerate this transition by the introduction of 1% of defects, or by modelling the effect of shear and pres sure fluctuations. The last method has proved successful, the system at 140 K undergoing a more rapid and distinct change of phase following the appli cation of a few short pressure pulses. The tentative suggestion that pressu re fluctuations are associated with nucleation remains open for further inv estigation. (C) 1999 Elsevier Science B.V. All rights reserved.