On the gas–liquid critical curves of different size hard-spheres binary mixtures interacting via the Lennard-Jones potential

Abstract

The critical behavior of binary mixtures represented by a potential model of different size hard spheres plus a Lennard-Jones interaction is studied by the application of thermodynamic perturbation theory. The Lennard-Jones potential function is the perturbing potential to the hard-sphere reference system. It is found that convexity of the critical curves of type I is sensitive to small changes of the unlike interaction parameter values. Results for Ar–Kr and CH4–Kr mixtures are in good agreement with experimental data.