中文摘要：

应用太赫兹时域光谱技术研究了反式油酸在THz波段的光学特性，在室温氮气环境下获得了0．5～2．5THz范围内波段的吸收光谱和折射率谱，结果表明反式油酸在此波段内存在多个特征吸收峰，样品的平均折射率为1．43。采用密度泛函理论的B3LPY方法对反式油酸分子的结构和振动频率进行了模拟，并采用Gaussian View软件对反式油酸分子的THz特征吸收峰进行了分析指认。实验结果与理论计算结果吻合较好，分析表明反式油酸在THz波段的吸收峰主要是由分子内振动和分子间振动共同引起的；同时，反式油酸在THz波段的指纹谱验证了太赫兹时域光谱技术用于反式油酸检测的可行性，为食品中反式脂肪酸的检测提供了新的实验方法。

英文摘要：

The optical properties of elaidic acid in the THz band were investigated by using THz time-domain spectroscopy （THZ-TDS）. The absorption and refractive index spectra in the frequency range from 0. 5 to 2. 5 THe were obtained at room temperature under nitrogen atmosphere, and the results show that elaidic acid had some characteristic absorption peaks, and the average refractive index of the sample was 1.43. The structure and vibrational frequencies of elaidic acid molecule in the THz range were simulated by the B3LYP algorithm of density functional theory, and the THz characteristic absorption peaks of elaidic acid molecule were identified by using Gaussian View software. The results show that the experimental and theoretical results agree in general, and the observed absorption peaks in the THz range were mainly caused by the intramolecular and intermolecular vibrations jointly. At the same time, the fingerprint spectra of elaidic acid in the THz band verify that the time-domain terahertz spectroscopy can be used to detect oleic acid, and this study provides a new experimental method for the detection of trans fatty acids in food.