INELASTIC NEUTRON-SCATTERING STUDY OF CS1-X(NH4)(X)HSO4 MIXED-CRYSTALS

Inelastic neutron scattering and X-ray diffraction study were performe d on Cs1-x(NH4)(x)HSO4 mixed crystals for x = 0.05 and 0.1. From the e xperimental data it follows that small concentrations of NH4 ions stab ilize phase II of pure CsHSO4 while this pure crystal undergoes a phas e transition into this phase only at elevated temperature. Comparative analysis of available data on optical spectroscopy of Cs1-xPbxHSO4 cr ystals reveals that small concentrations of Rb ions produce the same e ffect as NH4 ions. These observations allowed to make some conclusions about pressure-temperature-phase diagram of pure CsHSO4.