Comprehensive Benchmark Results for the Domain Based Local Pair Natural Orbital Coupled Cluster Method (DLPNO-CCSD(T)) for Closed- and Open-Shell Systems

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.