六氯铅铵晶体相变的拉曼散射研究  

Raman Scattering Study of Phase Transition in (NH_4)_2PbCl_6 Crystal

作　　者：史金荣 徐永晨[1] 吴翔[2] 

机构地区：[1]同济大学波耳固体物理研究所,上海200092 [2]中国科学院材料物理中心,沈阳110015

出　　处：《光学学报》1996年第6期727-731,共5页Acta Optica Sinica

摘　　要：在5K～300K的温度范围内对六氯铅铵晶体进行了拉曼散射测量，该晶体在Tc＝78K发生从立方结构（O5k）至三方结构（C23i）的二级相变．PbCl2-6八面体A1g模和NH4+四面体A1模的拉曼频移在Tc时出现极大值。八面体T2g模、四面体T2模和外振动T2g模在Tc以下发生连续分裂。另外在Tc以下观测到对应于高温相PbCl2-6八面体T1g模的软模。The Raman scattering measurement of ammonium hexachloroplumbate crystal has been presented. A second order structural phase transition from cubic (O5h) to trigonal structure (C23i) at Tc = 78 K was observed in this crystal. The Raman frequency shifts of the A1g mode of the PbCl2-6 octahedron and A1 mode of the ammoium tetrahedron have a maximum value at Tc Line splittings of the T2g mode of the PbCl2-6 octahedron, the Tzmodes of the ammonium tetrahedron and the external vibrational T2g mode have been observed below Tc, along with a soft mode corresponding to the T1g mode of the PbCl2-6 octahedron in the high temperature phase.

关 键 词：喇曼散射 结构相变 六氯铅铵 晶体 

分 类 号：O734.1[理学—晶体学]