Quadratic Unitary Coupled-Cluster Singles and Doubles Scheme: Efficient Implementation, Benchmark Study, and Formulation of an Extended Version
Quadratic Unitary Coupled-Cluster Singles and Doubles Scheme: Efficient Implementation, Benchmark Study, and Formulation of an Extended Version
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二次酉耦合簇单打和双打方案：有效实现、基准研究和扩展版本的制定
DOI：
10.1021/acs.jctc.1c01210
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发表时间：
2022
影响因子：
5.5
通讯作者：
Cheng, Lan
中科院分区：
文献类型：
--
作者：
Liu, Junzi;Matthews, Devin A.;Cheng, Lan
本文报道了一种利用非限制性分子自旋轨道公式和有效的张量收缩库计算电子基态和激发态的二次么正耦合团簇单双（qUCCSD）方案的有效实现.通过对激发能的广泛基准计算和对顺式和反式-4a，4 b-二氢苯并菲的S 0 → S1垂直激发能的应用，证明了qUCCSD方案的准确性和本实施方案的效率。与基于微扰理论制定的UCC 3方案相比，qUCCSD方案已被证明提供改进的激发能。为了进一步提高qUCCSD格式的精度，本文还提出了一种UCC截断格式，该格式可以提供四阶正确的激发能。
An efficient implementation of the quadratic unitary coupled-cluster singles and doubles (qUCCSD) scheme for calculations of electronic ground and excited states using an unrestricted molecular spin–orbital formulation and an efficient tensor contraction library is reported. The accuracy of the qUCCSD scheme and the efficiency of the present implementation are demonstrated using extensive benchmark calculations of excitation energies and an application to S0→ S1vertical excitation energies forcis- andtrans-4a,4b-dihydrotriphenylene. The qUCCSD scheme has been shown to provide improved excitation energies compared with the UCC3 scheme formulated based on perturbation theory. A UCC truncation scheme that can provide excitation energies correct through the fourth order is also presented to further improve the accuracy of the qUCCSD scheme.