Interpretation of the reduced density gradient

An interpretation of the reduced density gradient in terms of the bosonic kinetic energy density is presented. Contrary to other bonding indicators based on the kinetic energy density such as the localised orbital locator (LOL) or the electron localization function (ELF), the reduced density gradient is not only able to identify covalent bondings, but also ionic and non-covalent interactions. This study reveals that the critical points of the reduced density gradient are closely connected with those of LOL and with the roots of the one-electron potential (OEP).