Three-body interactions and the phase equilibria of mixtures

Gibbs ensemble Monte-Carlo simulations are reported for the vapour-liquid phase \ncoexistence of the binary argon - krypton mixture. The calculations employ accurate two-body \npotentials in addition to contributions from three-body dispersion resulting from third-order \ntriple-dipole interactions. The calculations are in good overall agreement with experiment. The \ncomposition of coexisting vapour and liquid phases is relatively unaffected by three-body interactions. \nIn contrast, three-body interactions affect substantially the density of the liquid phase.