Computerized implementation of higher-order electron-correlation methods and their linear-scaling divide-and-conquer extensions.
We have implemented a linear-scaling divide-and-conquer (DC)-based higher-order coupled-cluster (CC) and Møller-Plesset perturbation theories (MPPT) as well as their combinations automatically by means of the tensor contraction engine, which is a computerized symbolic algebra system. The DC-based energy expressions of the standard CC and MPPT methods and the CC methods augmented with a perturbation correction were proposed for up to high excitation orders [e.g., CCSDTQ, MP4, and CCSD(2)TQ ]. The numerical assessment for hydrogen halide chains, polyene chains, and first coordination sphere (C1) model of photoactive yellow protein has revealed that the DC-based correlation methods provide reliable correlation energies with significantly less computational cost than that of the conventional implementations. © 2017 Wiley Periodicals, Inc.
['Nakano|Masahiko|M|', 'Yoshikawa|Takeshi|T|', 'Hirata|So|S|', 'Seino|Junji|J|', 'Nakai|Hiromi|H|0000-0001-5646-2931']
linear-scaling tensor contraction engine divide-and-conquer method electron-correlation theory