组氨酸和精氨酸的太赫兹光谱研究

Vibrational spectrum of histidine and arginine in THz range

采用太赫兹时域光谱(THz-TDS)测试和理论模拟相结合的方法,研究了组氨酸和精氨酸在THz波段的光谱特性.THz-TDS测试的有效光谱范围为0.2—2.8THz,在该波段得到样品的特征吸收峰分别位于0.88,1.64,2.23THz(组氨酸)和0.99,1.47,2.60THz(精氨酸);运用Gaussian03半经验理论PM3和AM1算法,计算了两种分子在0.1—10.0THz波段的振动吸收谱,结果表明它们在该波段均具有多个特征吸收,其中在0.2—2.8THz波段的吸收峰位与实验吸收峰位相互对应并且符合较好;给出了与光谱特征吸收对应的分子振转模型,为认识分子对THz波的响应机制提供了帮助,也为分子鉴别及更宽有效光谱区的实验测试研究提供了科学依据.

This paper reports the spectral characteristics of histidine and arginine in THz range by calculation and terahertz timedomain spectroscopy （THz-TDS）. Absorption peaks are found at 0.88, 1.64,2.23 THz （for histidine） and 0.99, 1.47, 2.60 THz （for arginine） by THz-TDS, respectively. The vibrational absorption spectra of the two molecules are calculated based on semi-empirical theory in the range of 0.1-10 THz. The calculated spectrum exhibits many absorption peaks and the first three of them are well comparable with the experiment results in the range of 0.2-2.8 THz. The vibration rotation modes corresponding to the absorption peaks of the molecules are presented. These results mutually validated both approaches, and can further be used in identification of molecules and experimental research in wider effective spectral range.