ABSTRACT
Information theory (IT) [1-8] is one of the youngest branches of applied probability theory, in which probability ideas have been introduced into the elds of communication, control, and data processing. Its foundations were laid in the 1920s by Fisher [1] in his classical measurement theory and in the 1940s by Shannon [3] in his mathematical theory of communication. The electronic quantum state of a molecule is determined by the system wave function, the amplitude of the particle probability distribution that carries information. It is thus intriguing to explore the information content of electron probability distributions in molecules and to extract from it patterns of chemical bonds, reactivity trends, and other molecular descriptors (e.g., bond multiplicities [“orders”] and their covalent/ionic composition). Indeed, it directly follows from the Hohenberg-Kohn theorems of density functional theory (DFT) [9] that all properties of molecular systems are unique functionals of their electron density in their nondegenerate ground state. In this survey, some recent developments in IT probes of molecular electronic structure are summarized. In particular, this survey will examine information displacements due to subtle electron redistributions accompanying bond formation, explore locations of direct chemical bonds using nonadditive information contributions, and examine the pattern of entropic connectivities between atoms in molecules (AIM) resulting from molecular communications between atomic orbitals (AOs).
