Combining active-space coupled-cluster methods with moment energy corrections via the CC(P;Q) methodology, with benchmark calculations for biradical transition states.
Combining active-space coupled-cluster methods with moment energy corrections via the CC(P;Q) methodology, with benchmark calculations for biradical transition states.
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DOI：
10.1063/1.3700802
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发表时间：
2012-04
期刊：
影响因子：
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通讯作者：
Jun Shen;P. Piecuch
中科院分区：
文献类型：
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作者：
Jun Shen;P. Piecuch
我们最近提出了CC(P；Q)方法，该方法可以修正在活动空间耦合团簇(CC)或运动方程(EOM)CC计算中获得的能量，这些计算恢复了大部分非动力学和一些动态电子关联效应，因为在活性空间CC/EOMCC考虑中遗漏了更高阶的、主要是动力学的关联。结果表明，通过将CC方法与定义CC(t；3)近似的漏掉三重激发的CC方法与CC(P；Q)式修正相结合，可以极大地改善对双自由基过渡态的描述，包括所产生的能垒和总能量。
We have recently suggested the CC(P;Q) methodology that can correct energies obtained in the active-space coupled-cluster (CC) or equation-of-motion (EOM) CC calculations, which recover much of the nondynamical and some dynamical electron correlation effects, for the higher-order, mostly dynamical, correlations missing in the active-space CC/EOMCC considerations. It is shown that one can greatly improve the description of biradical transition states, both in terms of the resulting energy barriers and total energies, by combining the CC approach with singles, doubles, and active-space triples, termed CCSDt, with the CC(P;Q)-style correction due to missing triple excitations defining the CC(t;3) approximation.