Neutron diffraction studies of H2O/D2O at supercritical temperatures. A direct determination of gHH(r), gOH(r), and gOO(r)

Neutron diffraction studies are reported on H2O at temperatures of 300 and 400 °C. The method of isotopic substitution is applied to three mixtures of H2O and D2O, and the diffraction data are used to determine the three radial distribution functions gHH(r), gOH(r), and gOO(r). These results can be used to discuss changes in nearest neighbor structure between water molecules, and to assess the degree of usefulness of representative (usually pairwise) model potentials.