Ströker Philipp, Meier Karsten
Institut für Thermodynamik, Helmut-Schmidt-Universität/Universität der Bundeswehr Hamburg, Holstenhofweg 85, 22043 Hamburg, Germany.
J Chem Phys. 2024 Mar 7;160(9). doi: 10.1063/5.0196466.
Vapor-liquid equilibria and thermodynamic properties of saturated argon and krypton were calculated by semi-classical Monte Carlo simulations with the NpT + test particle method using ab initio potentials for the two-body and nonadditive three-body interactions. The NpT + test particle method was extended to the calculation of second-order thermodynamic properties, such as the isochoric and isobaric heat capacities or the speed of sound, of the saturated liquid and vapor by using our recently developed approach for the systematic calculation of arbitrary thermodynamic properties in the isothermal-isobaric ensemble. Generally, the results for all simulated properties agree well with experimental data and the current reference equations of state for argon and krypton. In particular, the results for the vapor pressure and for the density and speed of sound of the saturated liquid and vapor agree with the most accurate experimental data for both noble gases almost within the uncertainty of these data, a level of agreement unprecedented for many-particle simulations. This study demonstrates that the vapor-liquid equilibrium and thermodynamic properties at saturation of a pure fluid can be predicted by Monte Carlo simulations with high accuracy when the intermolecular interactions are described by state-of-the-art ab initio pair and nonadditive three-body potentials and quantum effects are accounted for.
采用NpT + 测试粒子方法，利用从头算势描述两体和非加性三体相互作用，通过半经典蒙特卡罗模拟计算了饱和氩气和氪气的气液平衡及热力学性质。通过我们最近开发的在等温等压系综中系统计算任意热力学性质的方法，将NpT + 测试粒子方法扩展到饱和液体和蒸汽的二阶热力学性质计算，如等容和等压热容或声速。一般来说，所有模拟性质的结果与实验数据以及氩气和氪气当前的参考状态方程吻合良好。特别是，蒸汽压以及饱和液体和蒸汽的密度和声速结果与这两种稀有气体最精确的实验数据几乎在这些数据的不确定度范围内相符，这种吻合程度在多粒子模拟中是前所未有的。这项研究表明，当用最先进的从头算对势和非加性三体势描述分子间相互作用并考虑量子效应时，蒙特卡罗模拟可以高精度预测纯流体饱和时的气液平衡和热力学性质。
