Skolkovo Institute of Science and Technology, Skolkovo Innovation Center, Moscow 121205, Russia.
J Chem Phys. 2019 Dec 7;151(21):214302. doi: 10.1063/1.5129583.
Static and dynamic polarizabilities of alkaline earth metal atoms Be-Ba and of the Yb atom, as well as dispersion coefficients and retardation functions for their long-range interactions, are used as a benchmark for the restricted coupled cluster method with singles and doubles (CCSD) and noniterative triples added [CCSD(T)] and related polarization propagator CCSD(3) methods at the complete basis set limit. The latter is attained through the sequence of the augmented correlation-consistent polarized weighted core valence n-zeta basis sets with the exact 2-component approximation for the scalar relativistic effects and with the small-core effective core potentials (for Ca, Sr, and Ba). At the converged level of core correlation treatment, the finite-field CCSD(T) method reproduces the best available data for the static dipole and quadrupole polarizabilities better than 1% and 4%, respectively. Systematic cancelation of the triple contribution in the CCSD(3) calculations of the dynamic polarizabilities of alkaline earth metal atoms makes their dispersion coefficients accurate within 3%. The retardation functions are computed and used for the analysis of the long-range interactions in the homonuclear dimers. Implications to accurate ab initio calculations of the global interaction potentials are discussed.
碱土金属原子 Be-Ba 和 Yb 原子的静态和动态极化率，以及它们长程相互作用的色散系数和延迟函数，被用作受限耦合簇方法（包括单双激发和非迭代三激发项[CCSD(T)]）和相关极化传播子 CCSD(3)方法在完全基组极限下的基准。后者通过增强相关一致极化加权核心价 n-zeta 基组的序列来实现，对于标量相对论效应采用精确的 2 分量近似，并采用小核有效核势（对于 Ca、Sr 和 Ba）。在核心相关处理的收敛水平上，有限场 CCSD(T)方法对静态偶极和四极极化率的最佳可用数据的再现精度优于 1%和 4%。在碱土金属原子的动态极化率的 CCSD(3)计算中，三重项的系统抵消使得它们的色散系数的精度在 3%以内。延迟函数被计算并用于分析同核二聚体中的长程相互作用。讨论了对全局相互作用势能进行精确从头计算的影响。
