【摘要】 采用太赫兹时域光谱和拉曼光谱法对L-苏氨酸多晶粉末进行测试研究,获得了样品在0.2—2.8THz(6.7—93.2cm-1)波段的特征吸收和10—4000cm-1波段的拉曼散射谱;分别在6.7—93.2cm-1和400—4000cm-1两个波段进行了吸收光谱与拉曼散射光谱的对比,根据晶胞分子所属的空间群,对隶属于分子的极性和非极性振动模式(A,B1,B2,B3对称类型)进行了指认;利用Gaussian08的B3LYP函数和6-311+G**基组计算了苏氨酸晶体的简正频谱,对所观察到的苏氨酸的全部THz吸收和低频拉曼散射峰所对应的振转模式进行了归属.更多还原

【Abstract】 The THz absorption within the range of 0.2—2.8 THz(6.7—93.2 cm-1)and Raman scattering spectra within the range of 10—4000 cm-1 of polycrystalline L-threonine have been examined with terahertz time-domain spectroscopy (THz-TDS) and Raman spectroscopy. Infrared spectrum between 400 and 4000 cm-1 were also recorded. We assigned the polar and the non-polar vibrational modes of the polycrystalline molecule in the range of both 6.7—93.2 cm-1 and 400—4000 cm-1 based on the theory of space group and the comparison of Raman and absorption spectra. Normal frequency vibrational modes were calculated for the single crystal form using the B3LYP method of density functional theory (DFT) and 6-311+G basis set. All the experimental THz absorption peaks and low frequency Raman scattering peaks of polycrystalline L-threonine were assigned.更多还原