Raman scattering of K₃D_xH_1-x(SO₄)₂

Abstract In mixed crystal of K3H(SO4)2 and K3D(SO4)2, the internal modes of HSO4 −, DSO4 − and SO2− were separately observed. In the ordered phase, the splittings between ω(HSO4 −) and ω(SO2−), and ω(DSO4 −) and ω(SO2−) depend on temperature as (Tc − T)β with β = 0.25 ± 0.05. In the disordered state, HSO4 − and DSO4 − lines show broadening near the transition temperature. Motional narrowing theory developed in nuclear magnetic resonance is applied to analyse the broadening and the correlation time for hydrogen (deuteron) motion is obtained.