Molecular simulation of complete phase diagrams for binary mixtures

Vapor-liquid, vapor-solid and liquid-solid coexistence lines are calculated for binary mixtures of Lennard-Jones spheres using Monte Carlo simulation and the Gibbs-Duhem integration technique. Complete phase diagrams showing equilibrium between vapor; liquid and solid phases are constructed for bina ry Lennard-Jones mixtures with diameter ratios ranging from sigma (11)/sigm a (22) = 0.85-1.0 and attractive well-depth ratios ranging from epsilon (11 )/epsilon (22) = 0.625 - 1.6, at a reduced pressure P* = P sigma (3/)(11)ep silon (11) = 0.002. The Lorentz-Berthelot combining rules are used to calcu late the cross-species interaction parameters sigma (12) and epsilon (12) T he variation in the shape of the complete phase diagrams change as a functi on of the diameter ratio sigma (11)/sigma (12), and well-depth ratio epsilo n (11)/epsilon (12) is systematically explored. The phase diagrams found he re resemble those Sound experimentally for argon-methane, iodine-sulfur; wa ter-sodium chloride, wave-silver nitrate, water-potassium nitrate, and p-di chlorobenzene-p-dibromobenzene.