Monte Carlo Equation of State for Hard Spheres in an Attractive Square Well

The equation of state for hard spheres in a short-range attractive square well has been calculated for several values of the well strength by the Monte Carlo method. For shallow wells, it has the same general form but lies everywhere below the equation of state for the simple hard-core potential. As the well strength increases, two van der Waals loops appear, one at a density higher than the density of the order—disorder transition and one at a lower density.