Monte Carlo simulation and phase behavior of nonadditive hard-core mixtures in two dimensions

We report Monte Carlo results for the thermodynamic and structural properties of a mixture of equally sized hard discs that are characterized by a nonadditive collision diameter for particles belonging to unlike species. We calculated the phase-coexistence lines relative to fluid-fluid demixing using a first-order perturbation theory. We also analyzed the onset of structural ordering in the mixture within a one-phase scheme based on the multiparticle correlation expansion of the statistical entropy, an approach that has been already used to study demixing in three dimensions. (C) 2002 American Institute of Physics.