A new pressure induced phase of the zero-dimensional hydrogen-bonded K3D(SO4)2studied by raman scattering

A first-order phase transition induced by pressure was newly found at 2·88 GPa and 258 K. The transition temperature Tp shifts upward with increasing pressure at a rate of about 80 K/GPa. The linewidth of the v 2 mode does not show any broadening near Tp and its frequency in the low temperature phase is almost independent of temperature. These facts are well explained by the character of the strong first-order phase transition.