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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。
Raman scattering measurements of hexachloro lead-ammonium crystals occurred at a temperature range of 5K to 300K, and the crystals undergo a second-order phase transition from the cubic structure (O5k) to the tri-structure (C23i) at Tc = 78K. The Raman shift of PbCl2-6 A1a mode and NH4 + tetrahedron mode A1 shows a maximum at Tc. The octahedral T2g mode, the tetrahedral T2 mode and the external vibration T2g mode undergo continuous division below Tc. In addition, a soft mode corresponding to the high temperature phase PbCl2-6 octahedral T1g mode was observed below Tc.