Finding chemical concepts in the Hilbert space: Coupled cluster analyses of noncovalent interactions

Noncovalent interactions (NCIs) play a major role in essentially all fields of chemical research. Energy decomposition analysis (EDA) schemes provide in-depth insights into their nature by decomposing interaction energies into additive contributions, such as electrostatics, polarization, and London dispersion. Although modern local variants of the “gold standard” coupled-cluster singles and doubles method plus perturbative triples (CCSD(T)) have made it possible to accurately quantify NCIs for relatively large systems, extracting chemically meaningful energy terms from such high level electronic structure calculations has been a long lasting challenge in computational chemistry. This review describes basic principles, interpretative aspects and applications of recently developed coupled cluster-based EDAs for the analysis of NCIs. The focus is on computationally efficient methods for systems with a few hundred atoms, for example, the recently introduced local energy decomposition analysis. In order to draw connections between different interpretative frameworks, these schemes are compared with other popular approaches for the quantification and analysis of NCIs, such as Symmetry Adapted Perturbation Theory and supermolecular EDAs based on mean-field as well as correlated approaches. Strengths and limitations of the various techniques are discussed. This article is characterized under: Electronic Structure Theory > Ab Initio Electronic Structure Methods Structure and Mechanism > Molecular Structures.