Ab initio calculations of the hydrogen bond -: art. no. 235101

Recent x-ray Compton scattering experiments in ice have provided useful information about the quantum nature of the interaction between H2O monomers. The hydrogen bond is characterized by a certain amount of charge transfer which could be determined in a Compton experiment. We use ab initio simulations to investigate the hydrogen bond in H2O structures by calculating the Compton profile and related quantities in three different systems, namely, the water dimer, a cluster containing 12 water molecules, and the ice crystal. We show how to extract estimates of the charge transfer from the Compton profiles.