Three‐body interactions in fluids from molecular simulation: Vapor–liquid phase coexistence of argon

Gibbs‐ensemble molecular simulations are reported for the vapor–liquid phase coexistence of argon using the two‐body Lennard‐Jones potential. During the simulation, the possible effect of three‐body interactions on the pressure and configurational energy of the vapor and liquid phases is estimated by performing calculations with three‐body potentials. The intermolecular potentials used for the three‐body calculations incorporate the influence of both three‐body‐dispersion and three‐body‐repulsion interactions. The results show that three‐body repulsion makes a significant contribution to three‐body interactions in the liquid phase. The effect of three‐body dispersion is offset substantially by three‐body repulsion.