Equation of state and force fields for Feynman-Hibbs-corrected Mie fluids. I. Application to pure helium, neon, hydrogen, and deuterium
Equation of state and force fields for Feynman-Hibbs-corrected Mie fluids. I. Application to pure helium, neon, hydrogen, and deuterium
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DOI：
10.1063/1.5111364
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发表时间：
2019-08-14
影响因子：
4.4
通讯作者：
Wilhelmser, Oivind
中科院分区：
文献类型：
--
作者：
Aasen, Ailo;Hammer, Morten;Wilhelmser, Oivind
我们提出了一个微扰理论，结合使用的三阶巴克-亨德森展开的亥姆霍兹能量与米氏势，包括第一（米氏FH 1）和第二阶（米氏FH 2）费曼-希布斯量子校正。由此产生的状态方程，统计关联流体理论Mie电位的变量范围校正量子效应（SAFT-VRQ-Mie），相比分子模拟，并被认为是准确地再现通用Mie-FH 1和Mie-FH 2流体的热力学性质。SAFT-VRQ米氏被用来获得最佳参数的氖，氦，氘，邻，帕拉，和正常的Mie-FH 1和Mie-FH 2配方的分子间的潜力。对于氦、氢和氘，与经典的米氏流体相比，使用一阶或二阶校正在超临界密度、热容和声速的表示中产生了显着更高的精度，尽管Mie-FH 2在超临界性质方面比Mie-FH 1稍微更准确。Mie-FH 1势被推荐用于大多数流体，因为它能更准确地表示纯组分的相平衡，并能更好地外推到低温。尽管如此，对于氦，量子效应是最大的，我们发现，没有一个势给出了一个准确的表示的整个相包络，其热力学性质准确表示只有在温度高于20 K。总的来说，超临界热容量得到了很好的代表，与氦和氢的液相区域中的实验有一些偏差。由AIP Publishing授权出版。
We present a perturbation theory that combines the use of a third-order Barker-Henderson expansion of the Helmholtz energy with Mie-potentials that include first- (Mie-FH1) and second-order (Mie-FH2) Feynman-Hibbs quantum corrections. The resulting equation of state, the statistical associating fluid theory for Mie potentials of variable range corrected for quantum effects (SAFT-VRQ-Mie), is compared to molecular simulations and is seen to reproduce the thermodynamic properties of generic Mie-FH1 and Mie-FH2 fluids accurately. SAFT-VRQ Mie is exploited to obtain optimal parameters for the intermolecular potentials of neon, helium, deuterium, ortho-, para-, and normal-hydrogen for the Mie-FH1 and Mie-FH2 formulations. For helium, hydrogen, and deuterium, the use of either the first- or second-order corrections yields significantly higher accuracy in the representation of supercritical densities, heat capacities, and speed of sounds when compared to classical Mie fluids, although the Mie-FH2 is slightly more accurate than Mie-FH1 for supercritical properties. The Mie-FH1 potential is recommended for most of the fluids since it yields a more accurate representation of the pure-component phase equilibria and extrapolates better to low temperatures. Notwithstanding, for helium, where the quantum effects are largest, we find that none of the potentials give an accurate representation of the entire phase envelope, and its thermodynamic properties are represented accurately only at temperatures above 20 K. Overall, supercritical heat capacities are well represented, with some deviations from experiments seen in the liquid phase region for helium and hydrogen. Published under license by AIP Publishing.