2001 年 70 巻 11 号 p. 3452-3456
Raman spectra of the langbeinite-type crystals K2Mn2(SO4)3 and (NH4)2Cd2(SO4)3 have been observed by using a micro-Raman scattering technique with a special attention to internal modes of SO4 molecules. The observed peaks are well assigned to the internal modes of SO4 in both the high- and low-temperature phases. At the phase transition temperature, new internal modes appear owing to the inequivalence of the molecular sites in the crystal. In addition, micro-Raman spectra have been observed at several positions on the surface of a single crystal. Micro-Raman spectra just at the transition temperature show either the high-temperature structure or the low-temperature structure as a function of the observed position. It is concluded that the sample single-crystal consists of the local regions which have different transition temperatures. This result indicates that not the intermediate phase but the coexistence of two phases appears in these langbeinite-type crystals.
この記事は最新の被引用情報を取得できません。
