Molecular clusters and correlations in water by x-ray and neutron diffraction

The combined analysis of x-ray- and neutron-diffraction data of liquid water and heavy water exhibits distinct molecular tetrahedral pentamer clusters (in ${\mathit{C}}_{2\mathit{v}}$ symmetry) in water due to hydrogen bonding. The center structure is derived from the diffraction data and used to evaluate through the model intermolecular partial structures and partial correlations in water. The results are compared with the available experimental and computer-simulated data.