An equation of state based on the intermolecular potential and the radial distribution function to estimate the virial coefficients by using PvT chaotic data

Abstract

We derive a new equation of state (EOS) for any non-polar, polar or quantum gas and any intermolecular potential through an approximation of the radial distribution function based on the Ornstein-Zernike equation. Such EOS is applied to estimate the virial coefficients B and C using two approaches. On one hand, B and C are directly computed from the proposed EOS considering the Mie potential for neon and water steam, which leads to values in very good agreement with the experimental data. On the other hand, the proposed EOS is applied in the context of a thermodynamic model to estimate B and C by fitting the simulated chaotic PvT data at an almost constant temperature. Such estimations of B and C are compared with the experimental values, which allows elucidating if B and C have a significant contribution on the virial equation at the considered pressures and temperatures. This methodology is applied to nitrogen and helium4 considering the intermolecular potentials of Mie, Morse, Kihara and Buckingham. For the considered gases and intermolecular potentials, the calculated values of B and C are in very good agreement with experimental data in a wide range of pressures and temperatures.