Monte Carlo calculations of the equation of state of the square-well fluid as a function of well width

Some results of Monte Carlo simulations for the square-well fluid for 1.125?λ?2, where λ-1 is the width of the well, are presented and compared with perturbation theory and, λ=1.85, with the BGY theory. In general, we find perturbation theory to be more reliable than the BGY theory. For λ≳1.5, perturbation theory is generally satisfactory. However, for λ<1.5, the pressures calculated from perturbation theory become less satisfactory as λ is decreased.