Density functional theory and Bader's atoms-in-molecules theory: towards a vivid dialogue

Abstract

Density functional theory and Bader's atoms-in-molecules theory share the same primary ingredient: the electron density, which is the fundamental physical observable in quantum chemistry. In this paper, we elaborate on the decomposition of the Kohn–Sham molecular energy in terms of Bader's partition, discussing how Pendás' Interacting Quantum Atoms framework could be adapted to a DFT context. Besides, another bridge between these two theories is built through a general formalism able to generate new local descriptors from any second-order density gradient expansion. These approaches are then applied to two classes of intramolecular bonds: between two electronegative atoms and intramolecular hydrogen bonds, illustrating how fruitful a dialog between both theories can be.