A comparative view on the potential acting on an electron in a molecule and the electrostatic potential through the typical halogen bonds.

This work considers the features of the electrostatic potential (ESP), and the potential acting on an electron in a molecule (PAEM) for the series of isolated dihalide molecules and for their molecular complexes. The joint analysis of these functions enriches the vision of atomic predispositions to the halogen bond formation and reveals details for their characterization. The account for the exchange-correlation interaction in PAEM retains the specific anisotropy of the ESP, which is commonly used for the halogen bonding explanation within σ-hole concept. Along the halogen bonds, the curvatures of PAEM and ESP functions are opposite. Being jointly mapped on the closed isosurfaces of the reduced density gradient, placed between bound atoms, they are significantly differed from the side facing the halogen atom and from the side looking at the electron donor atom. © 2017 Wiley Periodicals, Inc.