High-Pressure Raman and Infrared Spectroscopic Studies of Cesium Azide

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• 作者：Dongmei Li ; Peifen Zhu ; Junru Jiang ; Miaoran Li ; Yanmei Chen ; Bingbing Liu ; Xiaoli Wang ; Qiliang Cui ; Hongyang Zhu
• 刊名：Journal of Physical Chemistry C
• 出版年：2016
• 出版时间：December 1, 2016
• 年：2016
• 卷：120
• 期：47
• 页码：27013-27018
• 全文大小：558K
• ISSN：1932-7455

文摘

In this work, we present the effects of high pressure on the structure and stability of cesium azide (CsN₃) with the pressure up to ∼30.0 GPa, as studied by Raman and IR spectroscopy. Three phase transitions of Phase II → III → IV → V were revealed at ∼0.5, ∼3.7, and ∼16.0 GPa. The abnormal softening behavior of T(E_g) mode reveals the shearing distortion during Phase II → III transition. Moreover, changes of lattice modes and splitting of the degenerate T(E_g) and R(E_g) modes in Phase III indicate the breaking of crystallographically equivalent condition of azide ions. Phase IV was found to possess the C2/m structure, and Phase V has a lower symmetry structure than other phases. The IR measurements show the evolution of the N═N═N bending modes and the IR-active behavior of the symmetric stretch ν₁ mode under pressure, which collectively reveal the rotation and bending of the azide ions upon compression. The azide ions groups were found to further bend under pressure, and the bent azide ions might enhance propensity of nitrogen polymerization.