In this Letter, we extend our recent work [J. Chem. Phys. 138 (2013) 024102] on intramolecular O center dot center dot center dot Y interactions (Y being O, S, or a halogen atom) in the framework of Bader's atoms in molecules theory. The virial field as well as the variation rates of reduced density gradients and exchange energy density at the bond critical points are discussed, and new homogeneity descriptors are introduced. Finally, a fast and accurate method for the evaluation of interaction exchange energy, based on the sole electron density, is proposed. (C) 2013 Elsevier B.V. All rights reserved.