Some thermodynamic properties of fluids SF6, SF6–Ar, and SF6–Kr using new HFD-like potentials including three-body interactions: The inversion method and molecular dynamics simulation

Abstract

A new pair-potential energy function of sulfur hexafluoride has been determined via the inversion of reduced viscosity collision integrals at zero pressure and fitted to obtain a Hartree–Fock dispersion (HFD)-like potential form. The pair-potential reproduces the second virial coefficient and transport properties of sulfur hexafluoride in a good accordance with experimental data over wide ranges of temperatures. Molecular dynamics (MD) simulation has been also performed to obtain pressure, self-diffusion coefficient, and radial distribution function of fluid sulfur hexafluoride at different temperatures and densities using the calculated HFD-like pair-potential. We have also obtained pressures of SF6–Ar and SF6–Kr fluid mixtures at constant temperature at different densities using new two-body HFD-like models. To take higher-body forces into account, three-body potentials of Wang and Sadus (2006) [22,23] and Hauschild and Prausnitz (1993) [24] have been used with the two-body HFD-like potentials of SF6, SF6–Ar, and SF6–Kr systems to improve the prediction of the calculated properties without requiring an expensive three-body calculation. The MD simulation of sulfur hexafluoride has been also used to determine a new equation of state.