Abstract
Raman scattering from the deuterated compound Rb3D(SeO4)2 single crystal is studied in the temperature range between 79.2 K and 480.0 K. A new Raman line appears at 827 cm-1 as much as 60 K below the superionic phase transition temperature, and does not depend on temperature and deuteration. It has been suggested that this line is caused by the stretching motion of a single Se-O in SeO4 tetrahedra accompanied by the destruction and reconstruction of a hydrogen bond. In low temperature region, the dielectric constant of Rb3D(SeO4)2, measured at 100 KHz, shows a λ-type anomaly at 93 K, while the observed Raman spectra are almost the same above and below this temperature.
