Bonded Atoms from Information Theory

Abstract

The chemical concept of bonded atoms, the building blocks of molecules, is approached using the variational principles of IT. The Hirshfeld stockholder rule of partitioning the molecular density into pieces attributed to Atoms in Molecules (AIM) is derived from the principle of maximum information resemblance of AIM to the free constituent atoms defining the promolecular prototype. This principle can be straightforwardly extended into the related schemes for partitioning many-electron distributions, which give slightly different effective one-electron distributions for light AIM, compared with their Hirshfeld analogs. Representative information densities of such bonded atoms are presented and the combination relations between their charge sensitivities and the associated properties of the molecule as a whole are derived.