THERMODYNAMIC PROPERTIES OF THE LENNARD-JONES FLUID .1. SIMULATION DATA, RIGOROUS THEORIES AND PARAMETERIZED EQUATIONS OF STATE

The pressures and internal energies of the Lennard-Jones (LJ) fluid were calculated by using the Weeks-Chandler-Andersen theory, EXP (exponential) approximation, and the optimized reference HNC equation (RHNC). Comparison of the results with computer simulation data on eight isochores and seven isotherms shows that at reduced temperatures higher than 0.8 the RHNC theory predicts accurately the thermodynamic properties of the LJ fluid at all densities and that the EXP approximation performs also very well with the exception of a narrow range of conditions.