Local energy decomposition of coupled-cluster interaction energies: Interpretation, benchmarks, and comparison with symmetry-adapted perturbation theory

Local energy decomposition analysis provides a breakdown of the domain-based local pair natural orbital CCSD(T) [DLPNO-CCSD(T)] energy into additive contributions representing the interaction between pairs of user-defined fragments. Each of these fragment-pairwise components can be further decomposed into a sum of physically meaningful terms, such as electrostatics, dispersion, and exchange. In this study, the dependence of such energy terms on the basis set size, the approximations used for the two-electron integrals, and the localization scheme used for the virtual orbitals have been carefully evaluated on the interaction energies of the S66 benchmark set. A comparison with the energy components obtained at the SAPT2 + (3)δMP2 level of Symmetry-Adapted Perturbation Theory is also provided.