Quasiharmonic lattice-dynamics and molecular-dynamics calculations for the Lennard-Jones solids

We present molecular-dynamics (MD), quasiharmonic lattice-dynamics (QHLD), and energy-minimization calculations for the crystal structure of Ne, Ar, Kr, and Xe as a function of pressure and temperature. Lennard-Jones parameters are obtained for Ne, Kr, and Xe to reproduce the experimental pressure dependence of the density. We employ a simple method that combines results of QHLD and MD calculations to achieve densities in good agreement with experiment from 0 K to melting. Melting is discussed in connection with intrinsic instability of the solid as given by the QHLD approximation. [S0163-1829(98)02825-2].