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Abstract
In this study we examine the accuracy of domain-based local pair natural orbital coupled cluster theory with single, double, and perturbative triple excitations (DLPNO-CCSD(T)) on a large benchmark data set. To this end, we use the recently published GMTKN55 superset of molecules that contains 1505 relative energies and 2462 single-point calculations. To our knowledge this is the most comprehensive benchmark evaluation of any highly correlated wave function based ab initio method to date. In the first part of the study, canonical CCSD(T) reference calculations were carried out on the entire test set in order to guarantee that the reference data are of uniform quality. Second, DLPNO-CCSD(T) calculations were carried out under identical conditions. The main finding is that with the exception of two data sets, all data sets have a MAD of 0.4 kcal/mol or less and the majority of sets have a MAD of less than 0.2 kcal/mol. For open shells, the accuracy of the DLPNO calculations was significantly improved through an iterative version of the triples correction.
Highlights
The application of highly correlated wave function based quantum chemical methods to mainstream computational chemistry has come a long way in recent years
In this study we examine the accuracy of domain-based local pair natural orbital coupled cluster theory with single, double, and perturbative triple excitations (DLPNO-CCSD(T)) on a large benchmark data set
The accuracy of the domain based local pair natural orbital (DLPNO) calculations was significantly improved through an iterative version of the triples correction
Summary
The application of highly correlated wave function based quantum chemical methods to mainstream computational chemistry has come a long way in recent years. The combination of the size of the treated molecular systems and the accuracy in electronic energies that can be achieved today was unimaginable only a few years ago This increased applicability is to some extent the result of progress in computational hardware but, more importantly, rests on algorithmic developments. We will not attempt to review this large field of research here but will focus our attention on single-reference local coupled cluster approaches with single, double, and perturbative triple excitations (CCSD(T)) that are based on pair natural orbitals (PNO’s). Along slightly different lines Kaĺ lay and co-workers developed a natural orbitals based local CCSD(T) method.[41,42] Explicitly correlated versions of the PNO methods were reported by Tew, Haẗ tig, and co-workers,[40] Werner and co-workers,[22,28,30] and Valeev and co-workers.[14,43]
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