Near-Linear Scaling in DMRG-Based Tailored Coupled Clusters: An Implementation of DLPNO-TCCSD and DLPNO-TCCSD(T)

• DOI: 10.1021/acs.jctc.0c00065
• Publication Date: 2020-04-10T18:35:56Z
• Authors: Jakub Lang; Andrej Antalík; Libor Veis; Jan Brandejs; Jiří Brabec; Örs Legeza; Jiří Pittner
• Keywords: Linear scale

We present a new implementation of density matrix renormalization group based tailored coupled clusters method (TCCSD), which employs the domain-based local pair natural orbital approach (DLPNO). Compared to previous (LPNO) version method, is more accurate, offers favorable scaling, and provides consistent behavior across variety systems. On top singles doubles, we include perturbative triples correction (T), able retrieve even dynamic correlation. The methods were tested on three systems: tetramethyleneethane, oxo-Mn(Salen), iron(II)–porphyrin model. first two revisited assess performance with respect LPNO-TCCSD. For retrieved between 99.8 99.9% total canonical correlation energy an improvement 0.2% over LPNO in less than 63% runtime. Similar results obtained for iron(II)–porphyrin. When was employed, irrespective active space size or system, differences spin states within chemical accuracy 1 kcal/mol using default DLPNO settings.