Open-Shell Tensor Hypercontraction
Open-Shell Tensor Hypercontraction
复制标题
开壳张量超收缩
DOI：
10.1021/acs.jctc.3c00392
复制
发表时间：
2023
影响因子：
5.5
通讯作者：
Matthews, Devin A.
中科院分区：
文献类型：
--
作者：
Zhao, Tingting;Simons, Megan;Matthews, Devin A.
将最小二乘张量超收缩二阶和三阶 Møller-Plesset 微扰理论（LS-THC-MP2 和 LS-THC-MP3）扩展到开壳系统是一个重要的发展，因为 THC 提供了尺度减小以及分子离子、自由基和其他开壳反应物种的普遍存在。基于波函数的量子化学方法（例如 Møller-Plesset 和耦合簇理论）的复杂性反映在计算成本随分子大小的急剧变化上。最小二乘张量超收缩 (LS-THC) 方法是一种高效的双电子积分张量单步因式分解，但也可用于因式分解双激发振幅，从而显着缩小尺度。在这里，我们通过使用图解技术和显式自旋求和，将这种有希望的方法扩展到 LS-THC-MP2 和 -MP3 的开壳变体。由此产生的开壳物质方法的准确性以标准测试系统（例如常规烷烃）以及涉及断键、自由基稳定和其他效应的实际系统为基准。我们发现开壳 LS-THC-MPn 方法表现出的误差与闭壳 LS-THC-MPn 产生的误差非常相似，并且对特定化学相互作用、几何形状甚至中度自旋污染高度不敏感。
The extension of least-squares tensor hypercontracted second- and third-order Møller–Plesset perturbation theory (LS-THC-MP2 and LS-THC-MP3) to open-shell systems is an important development due to the scaling reduction afforded by THC and the ubiquity of molecular ions, radicals, and other open-shell reactive species. The complexity of wavefunction-based quantum-chemical methods such as Møller–Plesset and coupled cluster theory is reflected in the steep scaling of the computational costs with the molecular size. The least-squares tensor hypercontraction (LS-THC) method is an efficient, single-step factorization for the two-electron integral tensor but can also be used to factorize the double excitation amplitudes, leading to significant scaling reduction. Here we extend this promising method to open-shell variants of LS-THC-MP2 and -MP3 by using diagrammatic techniques and explicit spin summation. The accuracy of the resulting methods for open-shell species is benchmarked on standard test systems such as regular alkanes as well as realistic systems involving bond breaking, radical stabilization, and other effects. We find that open-shell LS-THC-MPnmethods exhibit errors highly comparable to those produced by closed-shell LS-THC-MPnand are highly insensitive to particular chemical interactions, geometries, or even moderate spin contamination.