McNeill Ashley S, Peterson Kirk A, Dixon David A
Department of Chemistry and Biochemistry, The University of Alabama, Tuscaloosa, Alabama 35487, USA.
Department of Chemistry, Washington State University, Pullman, Washington 99164, USA.
J Chem Phys. 2020 Nov 7;153(17):174304. doi: 10.1063/5.0026876.
Atomic polarizabilities play an important role in the development of force fields for molecular simulations, as well as for the development of qualitative concepts of atomic and molecular behavior. Coupled cluster theory at the coupled cluster singles doubles triples level with very large correlation-consistent basis sets with extended diffuse functions has been used to predict the polarizabilities of the atomic neutrals, mono-cations and mono-anions with a noble gas configuration. Additional corrections for scalar relativistic and spin-orbit effects were also included for the electron configurations of Kr, Xe, and Rn. The results are in excellent agreement with experiment or with other high level calculations where available. The current results for most of these species represent the best available values for the polarizabilities. The results show that the polarizability of H is very difficult to calculate without extremely diffuse functions. The polarizability of H is the largest value, 34.05 Å, calculated for all species in the current study. The polarizabilities of the remaining halogen anions are also the best available values. The polarizabilities of the halogen anions (excluding F) and H have a linear correlation with the electron affinity of the neutral atom. Spin-orbit effects, even for closed shell species, cannot be ignored for quantitative accuracy, and the inclusion of spin-orbit effects for Fr, Rn, and At increases the polarizability by 4%, 6%, and 15%, respectively.
原子极化率在分子模拟力场的发展以及原子和分子行为的定性概念发展中起着重要作用。耦合簇单双三重激发水平的耦合簇理论结合具有扩展弥散函数的非常大的相关一致基组，已被用于预测具有稀有气体构型的原子中性体、单阳离子和单阴离子的极化率。对于氪、氙和氡的电子构型，还包括了标量相对论和自旋轨道效应的额外校正。结果与实验或其他可用的高水平计算结果非常吻合。目前这些物种中大多数的结果代表了极化率的最佳可用值。结果表明，没有极弥散函数很难计算氢的极化率。氢的极化率是本研究中所有物种计算出的最大值，为34.05 Å。其余卤素阴离子的极化率也是最佳可用值。卤素阴离子（不包括氟）和氢的极化率与中性原子的电子亲和能呈线性相关。对于定量精度，即使对于闭壳层物种，自旋轨道效应也不能忽略，对于钫、氡和砹，包含自旋轨道效应分别使极化率增加4%、6%和15%。
