Thermomechanical properties of the WCA-Lennard-Jones model system in its fluid and solid states

Thermomechanical properties of the WCA-Lennard-Jones model system in its fluid and fcc crystalline states are computed via molecular dynamics (MD) simulations, both with constant volume (NVT) and with constant pressure (NPT). Data for the pressure, energy, specific heat, bulk and shear elasticity coefficients, and for other quantities are presented in graphical form, as functions of the density, for a few selected temperatures. Those quantities which can be computed from the free energy, in the fluid state, are compared with theoretical expressions based on a modified Camahan-Starling (CS) theory. This involves the second virial coefficient and a temperature-dependent effective volume of a particle for which various expressions are discussed. Good agreement between theory and simulation is found for a simple specific choice of the effective volume. Additional thermodynamical quantities are displayed graphically for this case. Some MD data are also given in tabular form in the appendix. (C) 1998 Elsevier Science B.V. All rights reserved.