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

Abstract

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.

Unveiling the complex pattern of intermolecular interactions responsible for the stability of the DNA duplex

“…This method has already found widespread applications in chemistry. [34][35][36][37][38][39] In particular, our analysis relies on the recently developed Hartree-Fock plus London Dispersion (HFLD) scheme for the -34). Due to the right-handed helical structure of B-DNA, the X(x) and Y(x + 1) bases are more distant than the X(x + 1) and Y(x) bases.…”

Supramolecular Approach to Tuning the Photophysical Properties of Quadrupolar Squaraines

“…The non-covalent interaction analysis has been performed within NCIPlot software ( Boto et al, 2020 ; Johnson et al, 2010 ; Contreras-Garcia et al, 2011 ) and AIMAll ( Keith, 2019 ; Bader, 1990 ; Popelier, 2000 ), and charge transfer indexes have been calculated with Multiwfn3.8 ( Lu and Chen, 2021 . LPNO-CCSD(T) counterpoise-corrected interaction energies have been obtained within the ORCA 4.2.1 package ( Neese et al, 2020a ; Neese et al, 2020b ; Neese, 2012 ; Neese, 2018 ; Altun et al, 2021 ).…”

Fragment Localized Molecular Orbitals

“…For frag 1 and frag 3 , i.e., the two aromatic rings, E ele is always opposite to the purely repulsive contribution Δ E el-prep , which, when summed with E ex represents the exchange-repulsion term ( E ex-rep ), i.e., the Pauli repulsion. 49 For all the energetic contributions, the symmetry of the system is reflected in a symmetry of the energy terms, with frag 1 and frag 3 interacting most favorably with helix 1 and helix 2 , respectively. Also, frag 2 is interacting in a symmetrical way with the two helices, with the total interaction energies differing by just 0.2 kcal/mol.…”