Simulations were performed by using a model which took account of many-body effects such as polarization, and the adaptation of the size of an anion to its current environment. It was found that the physical properties which were accurately modelled included phonon frequencies, phase transitions and solid-state diffusion. It was shown that the so-called compressional effect was much less marked in fluorides than in oxides. Nevertheless, it greatly affected the phase transition pressure. It was noted that polarization effects, particularly in the case of cations, played a critical role in permitting anion diffusion. The importance of a short-range contribution to cation polarization was emphasized.

N.T.Wilson, M.Wilson, P.A.Madden, N.C.Pyper: Journal of Chemical Physics, 1996, 105[24], 11209-19