The lines of extremes for the second derivatives of the Gibbs potential in the supercritical regions of substances

摘要: A parametric expression for the Gibbs potential was found using generalized Van Laar method free energy of a system. Since this is used in order to analyze behavior system supercritical region, well-studied soft spheres selected as reference This allows one find thermodynamic characteristics from known virial coefficients and available information on position critical point. The lines extremes second derivatives were calculated with Lennard-Jones interaction potential. line maxima isothermal compressibility constant-pressure heat capacity compared molecular-dynamics data. good agreement between theoretical calculations, which are based analytic functions domain, data shows absence third-order phase transition region.