Real‐Space In Situ Bond Energies: Toward A Consistent Energetic Definition of Bond Strength

Abstract

AbstractA rigorous definition of intrinsic bond strength based on the partitioning of a molecule into real‐space fragments is presented. Using the domains provided by the quantum theory of atoms‐in‐molecules (QTAIM) together with the interacting quantum atoms (IQA) energetic decomposition, we show how an in situ bond strength, matching all the requirements of an intrinsic bond energy, can be defined between each pair of fragments. Total atomization or fragmentation energies are shown to be equal to the sum of these in situ bond energies (ISBEs) if the energies of the fragments are measured with respect to their in‐the‐molecule state. These energies usually lie above the ground state of the isolated fragments by quantities identified with the standard fragment relaxation or deformation energies, which are also provided by the protocol. Deformation energies bridge dissociation energies with ISBEs, and can be dissected by using well‐known tools of real‐space theories of chemical bonding.

Aurora Costales Castro

Associate Professor

Associate Professor of Physical Chemistry at the University of Oviedo. Her research applies quantum chemical topology to study chemical bonding in solids, clusters, and molecular systems.

Evelio Francisco Miguélez

Associate Professor

Associate Professor of Physical Chemistry at the University of Oviedo. Expert in the development and application of quantum chemical topology methods, IQA analysis, and electron correlation descriptors.