Prediction of the thermophysical properties of pure neon, pure argon, and the binary mixtures neon-argon and argon-krypton by Monte Carlo simulation using ab initio potentials

Abstract

Gibbs ensemble Monte Carlo simulations were used to test the ability of intermolecular pair potentials derived ab initio from quantum mechanical principles, enhanced by Axilrod-Teller triple-dipole interactions, to predict the vapor-liquid phase equilibria of pure neon, pure argon, and the binary mixtures neon-argon and argon-krypton. The interaction potentials for Ne-Ne, Ar-Ar, Kr-Kr, and Ne-Ar were taken from literature; for Ar-Kr a different potential has been developed. In all cases the quantum mechanical calculations had been carried out with the coupled-cluster approach [CCSD(T) level of theory] and with correlation consistent basis sets; furthermore an extrapolation scheme had been applied to obtain the basis set limit of the interaction energies. The ab initio pair potentials as well as the thermodynamic data based on them are found to be in excellent agreement with experimental data; the only exception is neon. It is shown, however, that in this case the deviations can be quantitatively explained by quantum effects. The interaction potentials that have been developed permit quantitative predictions of high-pressure phase equilibria of noble-gas mixtures.

Role of three-body interactions in formation of bulk viscosity in liquid argon

“…Nasrabad et al 16 undertook a Monte Carlo simulation of argon using combination of ab initio pair interaction 4 and ATM triple-dipole dispersion interaction 10 to test their ability to predict vapor-liquid equilibrium. Although more accurate ab initio pair potentials for argon have become available recently, 5,6 and other many-body contributions to inter-atom interaction can be calculated, 8 we use the same interaction as Nasrabad et al because, being able to predict accurately the phase diagram of argon, 16 it is computationally more efficient.…”

“…Although more accurate ab initio pair potentials for argon have become available recently, 5,6 and other many-body contributions to inter-atom interaction can be calculated, 8 we use the same interaction as Nasrabad et al because, being able to predict accurately the phase diagram of argon, 16 it is computationally more efficient. Specifically, the ab initio pair interaction potential used in the present work is described by a function…”

“…[16]. The ATM triple-dipole interaction has form 10 u 3 (r 12 ,r 23 ,r 31 ) = ν 1 + 3 cos α cos β cos γ r …”

“…8,9 The most widely used of these contributions is triple-dipole dispersion interaction, derived by Axilrod and Teller 10,11 and Muto, 12 and account of this contribution in addition to ab initio pair potential is sufficient to describe thermodynamic properties of argon with good accuracy. [13][14][15][16][17] By virtue of Henderson theorem, 18,19 which states that, for fluids with only pairwise interactions, and under given conditions of temperature and density, the pair potential which gives rise to a given radial distribution function g(r)…”

Response to “Comment on ‘The gas-liquid surface tension of argon: A reconciliation between experiment and simulation”’ [J. Chem. Phys. 142, 107101 (2015)]

“…The real potentials of interest in our paper are the accurate two-body potentials of Barker-Fischer-Watts (BFW) 4 and Nasrabad-Laghaei-Deiters (NLD) 5 included in the NLD calculations, then the calculated liquid densities and vapor pressure would have been shifted by the same significant amount found for the LJ potential and that this throws some doubt on our conclusions.…”