Accurate thermodynamic properties of the neon fluid from ab initio potentials and uncertainty assessments of simulation data

Abstract

Molecular dynamics simulations are employed to investigate the internal energy, pρT properties, isochoric heat capacity, and sound speed of the neon fluid. Reliable two- and three-body ab initio potentials are used to obtain data covering a wide temperature and density range of (25 to 725) K and (0.05 to 70) mol⋅L−1 in the gas, liquid, and supercritical phases. The uncertainty of simulation data are evaluated based on the uncertainty of the two-body potential and that of the simulation method. The so-called quantum Feynman-Hibbs modification is introduced to account for the quantum effects at low temperatures. The two-body ab initio potential is combined with the three-body ab initio potential to evaluate the influence of multi-body interactions at high densities. The corresponding results are almost the same as those by the two-body ab initio potential, so the three-body contributions are neglected to accelerate computational speed. In general, the thermodynamic property data of this work show agreement with the experimental data in the literature as well as the NIST data at temperatures above 120 K and densities below 45 mol⋅L−1.