论文标题
显式相关的耦合簇方法，用于精确治疗数百个原子的开壳分子
Explicitly correlated coupled cluster method for accurate treatment of open-shell molecules with hundreds of atoms
论文作者
论文摘要
我们提供了明显相关的耦合群集单打的近乎线性缩放公式，并使用扰动的三胞胎方法（CCSD（t）$ _ {\ overline {\ overline {\ text {f text {f12}}} $）用于开放式shell shell shell shell shell的高素质状态。该方法基于常规的开放式CCSD形式主义[M. Saitow等人，J。Chem。物理。 146，164105（2017）]利用域局部对自然轨道（DLPNO）框架。使用与旋转的一组配对轨道相关的使用可确保与之前报道的封闭式形式主义确切一致，仅对成本的影响很小（例如，开放式形式主义仅比$ \ text {c} _ \ text {160} \ text {160} \ text {$ n text {$ n} $ n of $ \文本{测量的尺寸复杂性为$ \ of1.2 $）。在不到3天内的一台多核计算机上可行，可在一台多核计算机上可行地评估具有超过550个原子和5000个基函数的开放壳系统附近（CBS）限制（CBS）限制的耦合群集能量的评估。 aug-cc-pvtz dlpno-ccsd（t）$ _ {\ overline {\ text {f12}}} $贡献了348个核心燃烧物种基准中50个最大分子的形成热量的贡献[J. J. Klippenstein等人，J。Phys。化学A 121，6580（2017）]的根平方偏差（RMSD）来自外推CBS CCSD（t）参考值0.3 kcal/mol。对于更具挑战性的50种反应，涉及小的闭合和开放壳分子[G. Knizia等人，J。Chem。物理。 130，054104（2009）] aug-cc-pvq（+d）z dlpno-ccsd（t）$ _ {\ overline {\ text {f text {f12}} $产生的RMSD的RMSD为$ \ sim $ 0.4 kcal/mol，相对于CBS CCSD（T）eStimate。
We present a near-linear scaling formulation of the explicitly-correlated coupled-cluster singles and doubles with perturbative triples method (CCSD(T)$_{\overline{\text{F12}}}$) for high-spin states of open-shell species. The approach is based on the conventional open-shell CCSD formalism [M. Saitow et al., J. Chem. Phys. 146, 164105 (2017)] utilizing the domain local pair-natural orbitals (DLPNO) framework. The use of spin-independent set of pair-natural orbitals ensures exact agreement with the closed-shell formalism reported previously, with only marginally impact on the cost (e.g. the open-shell formalism is only 1.5 times slower than the closed-shell counterpart for the $\text{C}_\text{160}\text{H}_{\text{322}}$ n-alkane, with the measured size complexity of $\approx1.2$). Evaluation of coupled-cluster energies near the complete-basis-set (CBS) limit for open-shell systems with more than 550 atoms and 5000 basis functions is feasible on a single multi-core computer in less than 3 days. The aug-cc-pVTZ DLPNO-CCSD(T)$_{\overline{\text{F12}}}$ contribution to the heat of formation for the 50 largest molecules among the 348 core combustion species benchmark set [J. Klippenstein et al., J. Phys. Chem. A 121, 6580 (2017)] had root-mean-square deviation (RMSD) from the extrapolated CBS CCSD(T) reference values of 0.3 kcal/mol. For a more challenging set of 50 reactions involving small closed- and open-shell molecules [G. Knizia et al., J. Chem. Phys. 130, 054104 (2009)] the aug-cc-pVQ(+d)Z DLPNO-CCSD(T)$_{\overline{\text{F12}}}$ yielded a RMSD of $\sim$0.4 kcal/mol with respect to the CBS CCSD(T) estimate.
