Vapor–liquid equilibrium and thermodynamic properties of saturated argon and krypton from Monte Carlo simulations using ab initio potentials.

This article focuses on extending the NpT + test particle Monte Carlo simulation method to accurately calculate vapor–liquid equilibria and a comprehensive set of thermodynamic properties at saturation for pure fluids, specifically argon and krypton. Using highly accurate ab initio two-body and nonadditive three-body interaction potentials combined with semi-classical Feynman–Hibbs quantum corrections, the method predicts vapor pressure, chemical potential, densities, enthalpy of vaporization, and eight additional second-order properties—including heat capacities, compressibilities, speed of sound, and the Joule–Thomson coefficient. The simulation results for argon show excellent agreement with the current reference equation of state (TEOS) and experimental data, while krypton results exhibit somewhat larger deviations, attributed mainly to the less accurate three-body potential and equation of state (LSEOS) used. Overall, the study demonstrates that the extended NpT + test particle method, when combined with state-of-the-art interaction potentials and quantum corrections, can reliably predict vapor–liquid equilibrium and thermodynamic saturation properties of noble gases with high precision.