STRUCTURE AND PHASE-SEPARATION BEHAVIOR OF YUKAWA MIXTURES STUDIED BY THE MEAN-SPHERICAL APPROXIMATION AND COMPUTER CALCULATIONS

Nearly ideal and very nonideal binary Yukawa mixtures are studied with Monte Carlo (MC) and mean-spherical approximation (MSA) methods. Compressibility factors, static structure factors, and local mole fractions are compared in detail. The comparison shows that MSA predicts these properties of liquid Yukawa mixtures in sufficiently good agreement. Even for very nonideal mixtures the results of MC and MSA methods agree within about 10%. The phase unstability is also well predicted by MSA. The theoretical value lies only 8% lower than the "exact" one and falls practically in the uncertainty range of the MC result. We conclude that the mean-spherical theory is a suitable tool for describing the thermodynamics of these types of two-component systems reliably.