title: Are Bond Critical Points Really Critical for Hydrogen Bonding?
abstract: Atoms in Molecules (AIM) theory is routinely used to assess hydrogen bond formation; however its stringent criteria controversially exclude some systems that otherwise appear to exhibit weak hydrogen bonds. We show that a regional analysis of the reduced density gradient, as provided by the recently introduced Non-Covalent Interactions (NCI) index, transcends AIM theory to deliver a chemically intuitive description of hydrogen bonding for a series of 1,n-alkanediols. This regional definition of interactions overcomes the known caveat of only analyzing electron density critical points. In other words, the NCI approach is a simple and elegant generalization of the bond critical point approach, which raises the title question. Namely, is it the presence of an electron density bond critical point that defines a hydrogen bond or the general topology in the region surrounding it?
authors.affiliation: Department of Chemistry, University of Waikato, Private Bag 3105, Hamilton 3240, New Zealand.
authors.forename: Joseph R
authors.initials: JR
authors.lastname: Lane
authors.affiliation: UPMC Univ Paris 06, UMR 7616 CNRS, Laboratoire de Chimie Théorique, Case Courrier 137, 4 Place Jussieu, F-75005, Paris, France.
authors.forename: Julia
authors.initials: J
authors.lastname: Contreras-García
authors.affiliation: UPMC Univ Paris 06, UMR 7616 CNRS, Laboratoire de Chimie Théorique, Case Courrier 137, 4 Place Jussieu, F-75005, Paris, France.
authors.forename: Jean-Philip
authors.initials: JP
authors.lastname: Piquemal
authors.affiliation: Department of Chemistry, University of Otago, P.O. Box 56, Dunedin, New Zealand.
authors.forename: Benjamin J
authors.initials: BJ
authors.lastname: Miller
authors.affiliation: Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen Ø, Denmark.
authors.forename: Henrik G
authors.initials: HG
authors.lastname: Kjaergaard