Lang J, Przybytek M, Lesiuk M, Jeziorski B
Faculty of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw, Poland.
J Chem Phys. 2023 Mar 21;158(11):114303. doi: 10.1063/5.0137879.
We present the first-principles determination of the three-body polarizability and the third dielectric virial coefficient of helium. Coupled-cluster and full configuration interaction methods were used to perform electronic structure calculations. The mean absolute relative uncertainty of the trace of the polarizability tensor, resulting from the incompleteness of the orbital basis set, was found to be 4.7%. Additional uncertainty due to the approximate treatment of triple and the neglect of higher excitations was estimated at 5.7%. An analytic function was developed to describe the short-range behavior of the polarizability and its asymptotics in all fragmentation channels. We calculated the third dielectric virial coefficient and its uncertainty using the classical and semiclassical Feynman-Hibbs approaches. The results of our calculations were compared with experimental data and with recent Path-Integral Monte Carlo (PIMC) calculations [Garberoglio et al., J. Chem. Phys. 155, 234103 (2021)] employing the so-called superposition approximation of the three-body polarizability. For temperatures above 200 K, we observed a significant discrepancy between the classical results obtained using superposition approximation and the ab initio computed polarizability. For temperatures from 10 K up to 200 K, the differences between PIMC and semiclassical calculations are several times smaller than the uncertainties of our results. Except at low temperatures, our results agree very well with the available experimental data but have much smaller uncertainties. The data reported in this work eliminate the main accuracy bottleneck in the optical pressure standard [Gaiser et al., Ann. Phys. 534, 2200336 (2022)] and facilitate further progress in the field of quantum metrology.
我们给出了氦的三体极化率和第三介电维里系数的第一性原理确定结果。采用耦合簇和完全组态相互作用方法进行电子结构计算。发现由于轨道基组不完整导致的极化率张量迹的平均绝对相对不确定度为4.7%。由于对三重激发的近似处理和对更高激发的忽略而产生的额外不确定度估计为5.7%。开发了一个解析函数来描述极化率在所有碎片化通道中的短程行为及其渐近性。我们使用经典和半经典费曼 - 希布斯方法计算了第三介电维里系数及其不确定度。将我们的计算结果与实验数据以及最近采用三体极化率所谓叠加近似的路径积分蒙特卡罗（PIMC）计算结果[Garberoglio等人，《化学物理杂志》155, 234103 (2021)]进行了比较。对于高于200 K的温度，我们观察到使用叠加近似获得的经典结果与从头计算得到的极化率之间存在显著差异。对于10 K到200 K的温度，PIMC和半经典计算之间的差异比我们结果的不确定度小几倍。除了在低温下，我们的结果与现有实验数据非常吻合，但不确定度要小得多。这项工作中报告的数据消除了光压标准[Gaiser等人，《物理学年鉴》534, 2200336 (2022)]中的主要精度瓶颈，并促进了量子计量学领域的进一步发展。
