Lesiuk Michal
Faculty of Chemistry, University of Warsaw, Pasteura 1, 02-093, Warsaw, Poland.
J Comput Chem. 2019 May 5;40(12):1319-1332. doi: 10.1002/jcc.25788. Epub 2019 Feb 20.
We demonstrate a novel technique to obtain singular-value decomposition (SVD) of the coupled-cluster triple excitations amplitudes, . The presented method is based on the Golub-Kahan bidiagonalization strategy and does not require to be stored. The computational cost of the method is comparable to several coupled cluster singles and doubles (CCSD) iterations. Moreover, the number of singular vectors to be found can be predetermined by the user and only those singular vectors which correspond to the largest singular values are obtained at convergence. We show how the subspace of the most important singular vectors obtained from an approximate triple amplitudes tensor can be used to solve equations of the CC3 method. The new method is tested for a set of small and medium-sized molecular systems in basis sets ranging in quality from double- to quintuple-zeta. It is found that to reach the chemical accuracy (≈1 kJ/mol) in the total CC3 energies as little as 5 - 15% of SVD vectors are required. This corresponds to the compression of the amplitudes by a factor of about 0.0001 - 0.005. Significant savings are obtained also in calculation of interaction energies or rotational barriers, as well as in bond-breaking processes. © 2019 Wiley Periodicals, Inc.
我们展示了一种获得耦合簇三重激发振幅奇异值分解（SVD）的新技术。所提出的方法基于Golub-Kahan双对角化策略，并且不需要存储。该方法的计算成本与几次耦合簇单双激发（CCSD）迭代相当。此外，要找到的奇异向量的数量可以由用户预先确定，并且在收敛时仅获得那些对应于最大奇异值的奇异向量。我们展示了如何从近似三重振幅张量获得的最重要奇异向量的子空间可用于求解CC3方法的方程。该新方法在一系列从双ζ到五重ζ质量的基组中对一组中小分子系统进行了测试。结果发现，要在CC3总能量中达到化学精度（≈1kJ/mol），只需5 - 15%的SVD向量。这对应于将振幅压缩约0.0001 - 0.005倍。在相互作用能或旋转势垒的计算中，以及在断键过程中也获得了显著的节省。©2019威利期刊公司。
