Study on the Ferroelectric Phase Transition in RbDSO₄ by NMR. I. Deuteron Magnetic Resonance in Paraelectric Phase

抄録

The angular dependence of first order quadrupole shifts about three mutually perpendicular axes is measured at 20°C and is analysed by Volkoff method. Quadrupole coupling constants at two symmetrically inequivalent sites are 171.5±2.0 kHz in the hydrogen bond of 2.613 Å in length and 167.7±2.0 kHz in the other one of 2.712 Å in length. The directions of the principal axes of electric field gradient are discussed in connection with the position of deuterium in the hydrogen bond. It is concluded that the deuterium is not in a disordered state, but in fact stays on acentric position in each hydrogen bond even in the paraelectric phase.