Exact calculation of the effect of three-body Axilrod–Teller interactions on vapour–liquid phase coexistence

The Gibbs ensemble algorithm is implemented to determine the vapour–liquid phase coexistence of a pure fluid interacting via a two-body Lennard–Jones+three-body Axilrod–Teller potential. The contribution of both two-body and three-body interactions are calculated exactly. The results are compared with both experiment and two-body only simulation data. The position of the vapour branch of the coexistence curve is almost unaffected by the inclusion of three-body interactions. In contrast, the liquid branch occurs at substantially lower densities compared with Lennard–Jones simulation data. However, the approach to the critical point is improved by including three-body interactions, and the estimated critical point is in good agreement with the experiment.