On the physical role of exchange in the formation of an intramolecular bond path between two electronegative atoms

In this paper, we present a detailed energetic decomposition of intramolecular O center dot center dot center dot X interactions (X being O, S, or a halogen atom) based on the interacting quantum atoms approach of Pendas and co-workers. The nature of these interactions (repulsive or attractive, more or less electrostatic) is discussed in the framework of Bader's atoms in molecules theory, a particular emphasis being put on delocalization (measured by delocalization indexes and in terms of the source function) and on the exchange contributions. Notably, the concept of exchange channels introduced by Pendas and collaborators provides means of rationalizing and predicting the presence of bond critical points, enhancing the physical meaning of bond paths. (C) 2013 American Institute of Physics. [http://dx.doi.org/10.1063/1.4770495]