Phase equilibria and stability boundaries in a two component Lennard-Jones mixture

• Unified equation of state for a liquid and vapor Lennard-Jones (LJ) mixture obtained. • The mechanical and diffusion stability conditions of binary LJ mixtures are considered. • The phase equilibrium parameters are calculated. • The diffusion and mechanical spinodals of the mixture were determined. The mechanical and diffusion stability conditions of binary Lennard-Jones mixtures with respect to infinitesimal changes in state parameters are considered. In stable and metastable states, by molecular dynamics method, the pressure is determined as a function of temperature, density and composition of a Lennard-Jones mixture simulating the methane–nitrogen system. The phase equilibrium parameters are calculated. Based on the data obtained, a unified mixture state equation for liquid and vapor was created. The diffusion and mechanical spinodals of the mixture were determined.