An atoms-in-molecules model of bond energy distributions in polyatomic molecules

Abstract

A method is presented for describing the distribution of bonding energy at the equilibrium ground state conformation of a polyatomic molecule, based on Bader's atoms-in-molecules (AIM) formalism. The model can describe bonds of any order between a particular pair of atoms within a single set of parameters. It appears to be the first approach which successfully describes heteroatom-containing compounds. An additional feature of the model is that it provides an alternative method for quantifying strain and aromatic stabilization energies, quite different to the established approaches using isodesmic reactions. Also, the atoms-in-molecules nature of the model naturally leads to a kind of population analysis of the bonding energy distribution. Finally, the way in which the model might lead to ‘bond energy functionals’ and total energy functionals, which would be of considerable utility in interpreting experimentally-derived charge distributions, is discussed.