高压拉曼光谱研究均苯四甲酸二酐  

High-Pressure Raman Study of Pyromellitic Dianhydride

作　　者：丛广宇[1] 李东飞 刘嘉睿 CONG Guang-yu;LI Dong-fei;LIU Jia-rui(Department of Basic Education of Changchun Guanghua University,Changchun 130033,China;College of Physics,Changchun Normal University,Changchun 130032,China;College of Physics,Jilin Normal University,Siping 136000,China)

机构地区：[1]长春光华学院基础教研部,吉林长春130033 [2]长春师范大学物理学院,吉林长春130032 [3]吉林师范大学物理学院,吉林四平136000

出　　处：《光谱学与光谱分析》2024年第9期2434-2438,共5页Spectroscopy and Spectral Analysis

基　　金：国家自然科学基金项目(11904130);吉林省科技厅国际合作项目(20190701025GH);吉林省教育厅科学技术研究项目(JJKH20241640KJ,JJKH20241004KJ,JJKH20241319KJ)资助。

摘　　要：测量了常温常压下的均苯四甲酸二酐的拉曼光谱,并对所测量的各个拉曼谱线进行归属认证。获得了从常压到24GPa压强条件下的原位拉曼光谱,通过频率-压强关系曲线可以得出该材料在2Gpa存在晶体结构相变,定义了均苯四甲酸二酐在低于2GPa压强条件的晶体结构为相Ⅰ,高于2GPa压强条件的晶体结构相为相Ⅱ。在相变前后,绝大多数的拉曼谱线频率-压强曲线斜率变小,说明与相Ⅰ相比,各官能团对压强的敏感程度下降,相Ⅱ的分子晶体具有更紧密的堆积结构。拉曼光谱强度能够给出丰富的材料结构信息,通过对C—O伸缩振动的倍频(常压位于1837cm^(-1))和C=O伸缩振动基频(常压位于1865cm^(-1))的相对拉曼光谱强度随压强的变化规律进行分析,发现两拉曼谱线强度比在2GPa附近存在突变,为均苯四甲酸二酐在2GPa附近发生结构相变提供了实验依据。Raman spectra of pyromellitic dianhydride crystal have been measured from ambient to 24GPa,and the Raman vibrational modes of pyromellitic dianhydride have been assigned.Based on the pressure dependence of Raman mode frequencies,it can be observed that a phase transition of pyromellitic dianhydride occurred from PhaseⅠto PhaseⅡat 2GPa.In comparing the slopes of the pressure dependence of the Raman vibrational modes between PhaseⅠand PhaseⅡ,it can be found that most of the slopes of PhaseⅠwere smaller than PhaseⅡ.The results indicate that the sensitivity of functional groups of pyromellitic dianhydride to pressure decreases with increasing pressure,and the molecular crystal of pyromellitic dianhydride has a more compact stacking structure in phaseⅡ.Besides,we also calculated the Raman intensities ratio of the overtone of C—O stretching vibration mode(located at 1837cm^(-1))and the fundamental of C=O stretching vibration mode(located at 1865cm^(-1))and the discontinuities of the Raman intensities ratio versus pressure was observed.This behavior confirms that the pyromellitic dianhydride crystal has undergone a phase transition at 2GPa,as mentioned above.

关 键 词：拉曼光谱 高压 相变 均苯四甲酸二酐 

分 类 号：O433.4[机械工程—光学工程]