Abstract
We report Gibbs ensemble simulations of the coexistence region of the hard core two-Yukawa fluid with Yukawa parameters chosen to mimic the Lennard-Jones fluid. The phase envelope of the Lennard-Jones fluid is found to be well approximated by that of the Yukawa fluid. The results suggest that theoretical approaches to the hard core two-Yukawa fluid (such as integral equations and perturbation theory) could provide an analytic basis for predicting the physical properties of the Lennard-Jones fluid.