Observation of two O-H covalent bonds of water in the Na0.3 Co O2·1.3 H2 O superconductor by inelastic neutron spectroscopy

The vibrational dynamics of pure H2 O and isotopically substituted HDO water in a Na0.3 Co O2·1.3 H2 O layered compound was studied using neutron spectroscopy. The obtained results showed that water in the ab plane of the hexagonal structure exhibits intermolecular translational vibrations and intramolecular O-H stretching modes similar to those in bulk water, but the vibrations along the z direction are different-the corresponding hydrogen bond between the water molecule and the Co O2 layer is much weaker than between water molecules in the water layer. These data revealed two O-H covalent bonds for water in Na0.3 Co O2·1.3 H2 O superconductor which differ in strength by about 18%.