Solid-liquid phase equilibrium for binary Lennard-Jones mixtures

Solid-liquid phase diagrams are calculated for binary mixtures of Lennard-J ones spheres using Monte Carlo simulation and the Gibbs-Duhem integration t echnique of Kofke. We calculate solid-liquid phase diagrams for the model L ennard-Jones mixtures: argon-methane, krypton-methane, and argon-krypton, a nd compare our simulation results with experimental data and with Cottin an d Monson's recent cell theory predictions. The Lennard-Jones model simulati on results and the cell theory predictions show qualitative agreement with the experimental phase diagrams. One of the mixtures, argon-krypton, has a different phase diagram than its hard-sphere counterpart, suggesting that a ttractive interactions are an important consideration in determining solid- liquid phase behavior. We then systematically explore Lennard-Jones paramet er space to investigate how solid-liquid phase diagrams change as a functio n of the Lennard-Jones diameter ratio, sigma(11)/sigma(22), and well-depth ratio, epsilon(11)/epsilon(22). This culminates in an estimate of the bound aries separating the regions of solid solution, azeotrope, and eutectic sol id-liquid phase behavior in the space spanned by sigma(11)/sigma(22) and ep silon(11)/epsilon(22) for the case sigma(11)/sigma(22)<0.85. (C) 1999 Ameri can Institute of Physics. [S0021-9606(99)51122-7].