A SIMPLE EQUATION OF STATE FOR THE LENNARD-JONES FLUID - A NEW REFERENCE TERM FOR EQUATIONS OF STATE AND PERTURBATION THEORIES

A simple equation of state (EoS) for the Lennard-Jones (LJ) fluid that has a form similar to the Carnahan-Starling (CS) equation of state for the hard sphere fluid is presented. Excellent agreement between simulation data and calculated values for vapor pressures, saturated liquid and vapor densities and vapor PVT behavior is obtained for subcritical temperatures except in the critical region. For supercritical temperatures, the results are satisfactory but become less so with increased temperature and density. When combined with the van der Waals one fluid theory, the proposed equation provides satisfactory agreement with molecular simulation vapor-liquid equilibria results for binary LJ mixtures. Its overall behavior makes it suitable for use as a reference term in equations of state for real fluids.