Coupled-cluster method for open-shell heavy-element systems with spin-orbit coupling
Coupled-cluster method for open-shell heavy-element systems with spin-orbit coupling
复制标题
自旋轨道耦合开壳重元素系统的耦合簇方法
DOI：
10.1063/1.4979491
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发表时间：
2017-04-07
影响因子：
4.4
通讯作者：
Yang, Mingli
中科院分区：
文献类型：
--
作者：
Cao, Zhanli;Wang, Fan;Yang, Mingli
本文将基于相对论有效核势的后自洽场处理（SOC-CC）中包含自旋轨道耦合（SOC）的耦合团簇方法推广到空间非简并开壳层体系.采用对应于标量相对论哈密顿量的非限制Hartree-Fock行列式作为参考，在CCSD（singlelanddoubles）和CCSD（additionalbya tripleexcitation）（CCSD（T））水平上实现了开壳层SOC-CC方法.由于时间反演对称性和空间对称性的破坏，这种开壳层SOC-CC方法与闭壳层SOC-CC方法相比是相当昂贵的。开壳层SOC-CC方法被应用于具有s（1），p（3），sigma（1），pi（2）构型的开壳层原子和双原子分子。我们的结果表明，相当准确的结果可以实现与开壳层SOC-CCSD（T）的方法对这些系统。一些含有重IIIA或VIIA原子的闭壳层分子的解离能也使用闭壳层SOC-CC方法计算，其中IIIA或VIIA原子的能量是从闭壳层离子和实验电离势或电子亲合势获得的。SOC-CCSD（T）方法为这些分子提供了可靠的离解能。此外，采用相同策略的标量-相对论CCSD（T）方法也能为第5行IIIA或VIIA分子提供合理的离解能，而对第6行元素的离解能则有明显的误差。出版社：AIP Publishing
The coupled-cluster approach with spin-orbit coupling (SOC) included in post-self-consistent field treatment (SOC-CC) using relativistic effective core potentials is extended to spatially non-degenerate open-shell systems in this work. The unrestricted Hartree-Fock determinant corresponding to the scalar relativistic Hamiltonian is employed as the reference and the open-shell SOC-CC approach is implemented at the CC singles and doubles (CCSD) level as well as at the CCSD level augmented by a perturbative treatment of triple excitations (CCSD(T)). Due to the breaking of time-reversal symmetry and spatial symmetry, this open-shell SOC-CC approach is rather expensive compared with the closed-shell SOC-CC approach. The open-shell SOC-CC approach is applied to some open-shell atoms and diatomic molecules with s(1), p(3), sigma(1), or pi(2) configuration. Our results indicate that rather accurate results can be achieved with the open-shell SOC-CCSD(T) approach for these systems. Dissociation energies for some closed-shell molecules containing heavy IIIA or VIIA atoms are also calculated using the closed-shell SOC-CC approach, where energies of the IIIA or VIIA atoms are obtained from those of the closed-shell ions and experimental ionization potentials or electron affinities. SOC-CCSD(T) approach affords reliable dissociation energies for these molecules. Furthermore, scalar-relativistic CCSD(T) approach with the same strategy can also provide reasonable dissociation energies for the 5th row IIIA or VIIA molecules, while the error becomes pronounced for the 6th row elements. Published by AIP Publishing.