A NUCLEAR MAGNETIC RESONANCE STUDY OF THE MOBILITY OF WATER MOLECULES IN NaHC2O4*H2O

Article abstract of DOI:10.1016/0022-2860(88)85029-4

Diffusive dynamical properties of the water molecule in the compound NaHC2O4*H2O have been investigated by 1H NMR, measuring the spin-lattice relaxation time in the rotating frame (T_1ρ).A polycrystalline sample was used for measuring this relaxation time as a function of temperature, and a single crystal for measuring orientational dependence.One dynamical process has been found to be responsible for the relaxation: a 180 deg flip motion of H2O about its quasi twofold axis.The activation energy and the pre-exponential factor of the Arrhenius' relation for the correlation time of this motion are 62 kJ mol^-1 and 3.5x10^-16 s, respectively.Structural influence on the activation energy of the water flip motion is also discussed for five different solid hydrates.