Approximate kinetic energy density for intermolecular regions in hydrogen bond dimers

In a recent paper, Abramov [Y.A. Abramov, Acta Cryst. A53 (1997) 264] has proposed an approximation to compute the kinetic electron density G(r) from any electron density ρ(r) in the form of a truncated gradient expansion. This approach was known to provide accurate estimates of G(r) at the bond critical points of ρ(r). We show that Abramovʹs approach can be reliably used in spatial intermolecular regions in hydrogen fluoride and water dimers to obtain accurate estimates of the kinetic electron density. The study shows the usefulness of this approximated G(r) for quantum studies of intermolecular interactions in terms of ρ(r).