Charlotte Titeca

The use of electronic-structure theory to obtain total molecular properties has been standard practice for several decades. As atoms form the central building blocks of all chemistry, considerable interest has also been devoted to decomposing the total molecular energy into atomic contributions. Yet, molecular properties and chemical reactivity are not determined by atoms alone: molecules only materialize when their constituent atoms interact by forming bonds, and chemical reactions are driven by bond breaking and formation. Knowledge of the contributions of individual bonds to such properties could therefore provide insight into the influence of their local environments and help rationalize experimental observations. We present our recent efforts to develop new bond-centered decomposition schemes aimed at decomposing any arbitrary molecular property into local contributions associated with individual bonds. Starting from Eriksen’s atom-centered decomposition scheme, which relies on intrinsic atomic orbitals and localized molecular orbitals, the atomic contributions are redistributed into a quantum-chemical atom- and atom-pair-based decomposition. These contributions are subsequently further decomposed into conceptual bond-based components using an atom-to-bond mapping based on bond orders. Multiple approaches are explored and assessed through their application to a series of compounds containing a variety of functional groups.