Complete ab initio three-body nonadditive potential in Monte Carlo simulations of vapor–liquid equilibria and pure phases of argon

Complete ab initio three-body nonadditivity, including the short-range contributions, has been used for the first time in Monte Carlo simulations of liquid, gas, and liquid–vapor equilibrium of argon. Very good overall agreement with experiment has been achieved for phase equilibrium parameters and pV data of pure phases. The importance of various three-body interaction components has been assessed and their relationship to the liquid structure has been investigated. Although the short-range contributions to the nonadditivity are quite large, cancellations occurring between these and other components at the interatomic distances typical for the liquid make the total three-body nonadditive effect very similar to that given by a simple triple-dipole potential. Performance of the three-term virial equation of state is assessed based on the results of simulations.