Experimental quantum chemistry and chemical reactivity (Chapter 17)

Book chapter, 2023

This chapter describes a framework for chemical bonding analysis called Experimental Quantum Chemistry (EQC). In EQC, energies of atoms and molecules are partitioning into terms that can be both quantum mechanically calculated and experimentally estimated. EQC is here argued to be a conceptual bridge between Molecular Orbital (MO) theory and the general idea of Energy Decomposition Analysis (EDA), as well as quantum chemical topology-based techniques. The EQC framework allows for the design of descriptors useful for distinguishing bonds and for predicting chemical reactivity. The average electron energy is an example of a central component of EQC. This descriptor of electronic structure can be analyzed over subsets of electronic levels, as these vary over chemical reactions, and as spatially resolved over molecules. Electronegativity is in EQC defined as the average binding energy of valence electrons, which has allowed the extension of that central chemical concept to conditions of high pressure.