Symmetric and asymmetric triple excitation corrections for the orbital-optimized coupled-cluster doubles method: Improving upon CCSD(T) and CCSD(T)Λ: Preliminary application
Symmetric and asymmetric triple excitation corrections for the orbital-optimized coupled-cluster doubles method: Improving upon CCSD(T) and CCSD(T)Λ: Preliminary application
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DOI：
10.1063/1.4720382
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发表时间：
2012-05-28
影响因子：
4.4
通讯作者：
Schaefer, Henry F., III
中科院分区：
文献类型：
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作者：
Bozkaya, Ugur;Schaefer, Henry F., III
研究了轨道优化耦合团簇双星(OO-CCD或简称OD)方法的对称和非对称三重激发修正。实现了常规的对称和非对称摄动三重修正[(T)和(T)(Lambda)]，后者是第一次。此外，还引入了两个新的三元组修正，分别记为OD(Lambda)和OD(Lambda)(T)。我们将新方法应用于BH、HF、C-2、N-2和CH4分子的势能面，并将全组态相互作用下的总能量误差与标准耦合簇单和双团簇(CCSD)、微扰三重[CCSD(T)]和不对称三重修正(CCSD(T)(Lambda))方法的总能量误差进行了比较。CCSD(T)方法在拉伸几何结构上严重失效，相应的非平行度误差为7-281千卡·摩尔(-1)，尽管它在平衡几何结构附近给出了可靠的结果。对于BH、HF和CH4，新的对称三重校正CCSD(Lambda)显著优于CCSD(T)(提高4-14千卡摩尔(-1))；但对于C-2和N-2，其性能不如CCSD(T)(提高1.6-4.2千卡摩尔(-1))。对于BH、HF和CH4分子，CCSD(T)(Lambda)和CCSD(Lambda)(T)显著优于CCSD(T)(5-18千卡摩尔(-1))，而对于C-2和N-2，它们的结果与CCSD(T)相似。虽然CCSD和OD的性能相似，但在三次校正的情况下情况明显不同，特别是在拉伸几何图形的情况下。OD(T)法比CCSD(T)法提高1-279kcal摩尔(-1)。新的对称三重校正OD(Lambda)改进了BH、HF和CH4的OD(T)结果(提高了0.01-2.0千卡摩尔(-1))，但对C-2和N-2的结果不如OD(T)(提高1.9-2.3千卡摩尔(-1))。OD(T)(Lambda)和OD(Lambda)(T)比OD(T)好(2.0-6.2千卡摩尔(-1))。对于BH、HF和CH4分子，后一种方法稍好一些。然而，对于C-2和N-2，新的结果与OD(T)的结果相似。对于BH、HF和CH4分子，OD(Lambda)(T)方法提供的势能曲线最好，而对于C-2和N-2分子，OD(T)方法占优势。因此，对于单键断裂，OD(Lambda)(T)方法表现出更好的性能，而对于多键断裂，OD(T)方法表现得更好。(C)2012年美国物理研究所。[http://dx.doi.org/10.1063/1.4720382]
Symmetric and asymmetric triple excitation corrections for the orbital-optimized coupled-cluster doubles (OO-CCD or simply "OD" for short) method are investigated. The conventional symmetric and asymmetric perturbative triples corrections [(T) and (T)(Lambda)] are implemented, the latter one for the first time. Additionally, two new triples corrections, denoted as OD(Lambda) and OD(Lambda)(T), are introduced. We applied the new methods to potential energy surfaces of the BH, HF, C-2, N-2, and CH4 molecules, and compare the errors in total energies, with respect to full configuration interaction, with those from the standard coupled-cluster singles and doubles (CCSD), with perturbative triples [CCSD(T)], and asymmetric triples correction (CCSD(T)(Lambda)) methods. The CCSD(T) method fails badly at stretched geometries, the corresponding nonparallelity error is 7-281 kcal mol(-1), although it gives reliable results near equilibrium geometries. The new symmetric triples correction, CCSD(Lambda), noticeably improves upon CCSD(T) (by 4-14 kcal mol(-1)) for BH, HF, and CH4; however, its performance is worse than CCSD(T) (by 1.6-4.2 kcal mol(-1)) for C-2 and N-2. The asymmetric triples corrections, CCSD(T)(Lambda) and CCSD(Lambda)(T), perform remarkably better than CCSD(T) (by 5-18 kcal mol(-1)) for the BH, HF, and CH4 molecules, while for C-2 and N-2 their results are similar to those of CCSD(T). Although the performance of CCSD and OD is similar, the situation is significantly different in the case of triples corrections, especially at stretched geometries. The OD(T) method improves upon CCSD(T) by 1-279 kcal mol(-1). The new symmetric triples correction, OD(Lambda), enhances the OD(T) results (by 0.01-2.0 kcal mol(-1)) for BH, HF, and CH4; however, its performance is worse than OD(T) (by 1.9-2.3 kcal mol(-1)) for C-2 and N-2. The asymmetric triples corrections, OD(T)(Lambda) and OD(Lambda)(T), perform better than OD(T) (by 2.0-6.2 kcal mol(-1)). The latter method is slightly better for the BH, HF, and CH4 molecules. However, for C-2 and N-2 the new results are similar to those of OD(T). For the BH, HF, and CH4 molecules, OD(Lambda)(T) provides the best potential energy curves among the considered methods, while for C-2 and N-2 the OD(T) method prevails. Hence, for single-bond breaking the OD(Lambda)(T) method appears to be superior, whereas for multiple-bond breaking the OD(T) method is better. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4720382]