QUASI-HARMONIC LATTICE-DYNAMICS AND MOLECULAR-DYNAMICS CALCULATIONS FOR THE LENNARD-JONES SOLIDS

We present molecular-dynamics (MD), quasiharmonic lattice-dynamics (QH LD), 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 exp erimental pressure dependence of the density. We employ a simple metho d that combines results of QHLD and MD calculations to achieve densiti es in good agreement with experiment from 0 K to melting. Melting is d iscussed in connection with intrinsic instability of the solid as give n by the QHLD approximation. [S0163-1829(98)02825-2].