Behavior of a Binary Asymmetric Mixture of Interacting Particles in the Supercritical Region

Abstract

We propose a method for describing the phase behavior of a system consisting of particles of two sorts. The interaction of each species is described by interaction potentials containing the repulsive and attractive components. Asymmetry is ensured by different values of the interaction potentials of each sort. The grand partition function of a binary mixture is calculated in the zero-mode approximation. A line of critical points, which correspond to different proportions of the components, is calculated for specific values of parameters of the interaction potential. We have obtained an equation that relates the introduced mixing parameter x to the concentration of the system. An explicit expression of the pressure of the binary mixture is derived as a function of the relative temperature and the mixing parameter x to plot the Widom line. It is established that, for boundary values of this parameter (x = 0 and x = 1), the equation of state of a mixture turns into equations of state of its separate species.