北京大学学报自然科学版 ›› 2025, Vol. 61 ›› Issue (1): 121-129.DOI: 10.13209/j.0479-8023.2024.086

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NH4Cl的高压相变及弹性性质实验研究

张静宜1, 黄圣轩1,2, 秦善1,†   

  1. 1. 造山带与地壳演化教育部重点实验室, 北京大学地球与空间科学学院, 北京 100871 2. Geodynamics Research Center, Ehime University, Ehime 790-8577
  • 收稿日期:2023-12-07 修回日期:2024-01-22 出版日期:2025-01-20 发布日期:2025-01-20
  • 通讯作者: 秦善, E-mail: sqin(at)pku.edu.cn
  • 基金资助:
    国家自然科学基金(42072047)资助

Phase Transitions and Elastic Properties of NH4Cl at High Pressures

ZHANG Jingyi1, HUANG Shengxuan1,2, QIN Shan1,†   

  1. 1. The Key Laboratory of Orogenic Belts and Crustal Evolution (MOE), School of Earth and Space Sciences, Peking University, Beijing 100871 2. Geodynamics Research Center, Ehime University, Ehime 790-8577
  • Received:2023-12-07 Revised:2024-01-22 Online:2025-01-20 Published:2025-01-20
  • Contact: QIN Shan, E-mail: sqin(at)pku.edu.cn

摘要:

在高压环境下, 对天然卤砂(NH4Cl)进行同步辐射单晶X射线衍射(XRD)、拉曼光谱和红外光谱分析。结果表明, NH4Cl在13.6 GPa 发生相变, 从IV相(空间群为)变为V相(空间群为P4/nmm); IV相和V相NH4Cl的三阶Birch-Murnaghan状态方程参数分别为 K0=24.9(1) GPa, V0=56.4(1) Å3, K0′=5.5以及K0=35(25) GPa, V0=110(11) Å3, K0′=3.8(13)。NH4Cl的拉曼光谱在13.7 GPa出现新峰和不连续变化, 其拉曼位移与压强呈现线性关系, 据此获得IV相和V相NH4Cl各拉曼振动的位移量随压强的变化, 并计算格林乃森参数。NH4Cl的红外光谱在11.7~14.8 GPa出现N—H振动峰分裂。NH4Cl, NH4Br和NH4I的IV-V相变压强依次降低, 表现出与阴离子半径成反比的规律。

关键词: 氯化铵, 高压结构相变, X射线衍射, 拉曼光谱, 红外光谱

Abstract:

Synchrotron radiation single crystal X-ray diffraction (XRD), Raman spectroscopy and infrared spectroscopy were used to analyze natural ammonium chloride (NH4Cl) under high pressure. The results show that NH4Cl transforms from phase IV (space group ) to phase V (space group P4/nmm) at 13.6 GPa. The parameters of the third-order Birch-Murnaghan equation of state are determined with K0=24.9(1) GPa, V0=56.4(1) Å3, K0′=5.5 for phase IV, and K0=35(25) GPa, V0=110(11) Å3, K0′=3.8(13) for phase V. The Raman spectrum of NH4Cl shows new peaks and discontinuity at 13.7 GPa, and the Raman shift are linearly related to pressure. dνi/dP and Grüneissen parameters for each vibration of phase IV and V are obtained. The infrared spectrum of N—H vibration split at 11.7–14.8 GPa. The transition pressures from phase IV to V of NH4Cl, NH4Br and NH4I decrease in turn, which are inversely proportional to the anion radius. 

Key words: ammonium chloride, high pressure phase transition, X-ray diffraction, Raman spectroscopy, infrared spectroscopy