HIGH-PRESSURE RAMAN-STUDY OF ONE-DIMENSIONAL CRYSTALS OF THE VERY POLAR MOLECULE HYDROGEN-CYANIDE
HIGH-PRESSURE RAMAN-STUDY OF ONE-DIMENSIONAL CRYSTALS OF THE VERY POLAR MOLECULE HYDROGEN-CYANIDE
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DOI：
10.1103/physrevb.42.4298
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发表时间：
1990-09-01
影响因子：
3.7
通讯作者：
NICOL, M
中科院分区：
文献类型：
--
作者：
AOKI, K;BAER, BJ;NICOL, M
在环境温度下，氰化氢在0.2 GPa下冻结，并在0.8 GPa下经历固-固转变。超过1.3GPa的压缩引起聚合。在0.2和0.8 GPa之间以及0.8 GPa以上稳定的晶体结构分别被确定为体心四方晶系和正交晶系结构，它们也发生在低温和环境压力下。这两种结构都由平行于晶胞c轴排列的线性分子链组成。由于压缩增强了链内氢键，因此在两个固相中，内部CH伸缩模式的拉曼峰随着压力的增加而向较低频率移动。拉曼活性振动的频率迅速增加，随着压力的增加，在四方相，并在一个更大的速率在正交相。振动模的LO-TO分裂，ω LO-ω TO，随着压力的增加而单调减小，而这些频率的平方之差，ω LO 2-ω TO 2，与压力无关。
At ambient temperature, hydrogen cyanide freezes at 0.2 GPa and undergoes a solid-solid transition at 0.8 GPa. Compression beyond 1.3 GPa induces polymerization. The crystal structures stable between 0.2 and 0.8 GPa and above 0.8 GPa were identified as the body-centered tetragonal and orthorhombic structures, respectively, that also occur at low temperatures and ambient pressure. Both structures consist of linear chains of molecules aligned parallel to the c axis of the unit cell. The Raman peak for the internal CH stretching mode shifts to lower frequency with increasing pressure in both solid phases because compression strengthens the intrachain hydrogen bond. The frequency of the Raman-active libration increases rapidly with increasing pressure in the tetragonal phase and at an even greater rate in the orthorhombic phase. The LO-TO splitting of the librational mode, ω LO-ω TO, decreases monotonically with increasing pressure, whereas the difference between the squares of these frequencies, ω LO 2-ω TO 2, is independent of pressure.