Analysis of weakly bound structures: hydrogen bond and the electron density in a water dimer

The formation of the hydrogen bond is investigated in terms of the charge density. The water dimer is chosen as an example, and the redistribution of the electrons due to the H-bond is discussed. The density difference between interacting and non-interacting monomers is partitioned using localized orbitals and localized partial densities. Although the change in the electronic density is not completely described by the deformation of the two localized orbitals, OH bond and the appropriate lone pair orbital, the binding region is already well characterized with these local densities. (C) 2003 Published by Elsevier B.V.