Perturbative triples correction to domain-based local pair natural orbital variants of Mukherjee's state specific coupled cluster method

Abstract

In this article we report an implementation of the perturbative triples correction to Mukherjee's state-specific multireference coupled cluster method based on the domain-based pair natural orbital approach (DLPNO-MkCC). We tested the performance of DLPNO-MkCCSD(T) in calculations involving tetramethyleneethane and isomers of naphthynes.

These tests show that more than 97% of triples energy was recovered with respect to the canonical MkCCSD(T) method, which together with the DLPNO-MkCCSD part accounts for about 99.70-99.85% of the total correlation energy. The applicability of the method was demonstrated on calculations of singlet-triplet gaps for several large systems: triangulene, dynemicin A, and a beryllium complex.

Keywords

• electron correlation methods
• quadruply excited clusters
• configuration-interaction
• PNO-CI
• approximate account
• molecular-systems
• model systems
• ground-state
• dynemicin-A
• equations