The free energies of vacancy pair formation and migration were computed using molecular dynamics methods involving free-energy integrations and a non-empirical ionic model with no adjustable parameters. The intrinsic diffusion constant was obtained for pressures ranging from 0 to 140GPa, and temperatures ranging from 1000 to 5000K. Excellent agreement was found, with zero-pressure diffusion data, to within experimental error. The homologous temperature model, which related diffusion to the melting curve, closely described the high-pressure results for this theoretical framework.

J.Ita, R.E.Cohen: Physical Review Letters, 1997, 79[17], 3198-201