Thermophysical properties of krypton-helium gas mixtures from ab initio pair potentials.
Thermophysical properties of krypton-helium gas mixtures from ab initio pair potentials.
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DOI：
10.1063/1.4984100
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发表时间：
2017-06
期刊：
影响因子：
--
通讯作者：
B. Jäger;E. Bich
中科院分区：
文献类型：
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作者：
B. Jäger;E. Bich
利用超分子从头计算，建立了氪氦原子对34个原子间距离的势能曲线。用单、双、微扰三重激励下的耦合簇法计算得到了完全基集极限下的相互作用能，相关一致基集达到了六倍zeta质量，增加了中键函数。在连续修正项的方案中考虑了高阶耦合簇激励，直至完整的四重级。包括核心-核心和核心-价相关效应。相对论修正不仅在标量相对论水平上考虑，而且还使用全四分量狄拉克-库仑和狄拉克-库仑-冈特计算。拟合的分析偶势函数的井深为31.42 K，估计标准不确定度为0.08 K。应用统计热力学计算了氪氦交叉秒维里系数。计算结果与最佳实验数据吻合良好。基于经典和量子力学方法的碰撞动力学的动力学理论计算被用于计算大温度范围内稀气极限下氪氦混合物的输运性质。根据动力学理论的近似阶数对计算结果进行了分析，并与实验数据进行了比较。特别是二元扩散系数的数据证实了新势的预测质量。此外，从文献中可以解决氪-氦系统的两个经验对势函数之间的不一致性。
A new potential energy curve for the krypton-helium atom pair was developed using supermolecular ab initio computations for 34 interatomic distances. Values for the interaction energies at the complete basis set limit were obtained from calculations with the coupled-cluster method with single, double, and perturbative triple excitations and correlation consistent basis sets up to sextuple-zeta quality augmented with mid-bond functions. Higher-order coupled-cluster excitations up to the full quadruple level were accounted for in a scheme of successive correction terms. Core-core and core-valence correlation effects were included. Relativistic corrections were considered not only at the scalar relativistic level but also using full four-component Dirac-Coulomb and Dirac-Coulomb-Gaunt calculations. The fitted analytical pair potential function is characterized by a well depth of 31.42 K with an estimated standard uncertainty of 0.08 K. Statistical thermodynamics was applied to compute the krypton-helium cross second virial coefficients. The results show a very good agreement with the best experimental data. Kinetic theory calculations based on classical and quantum-mechanical approaches for the underlying collision dynamics were utilized to compute the transport properties of krypton-helium mixtures in the dilute-gas limit for a large temperature range. The results were analyzed with respect to the orders of approximation of kinetic theory and compared with experimental data. Especially the data for the binary diffusion coefficient confirm the predictive quality of the new potential. Furthermore, inconsistencies between two empirical pair potential functions for the krypton-helium system from the literature could be resolved.