中文摘要：

甜味剂是一种非常重要的食品添加剂,在食品工业中的应用十分广泛,甜味剂的鉴别和检测是一个非常重要的研究课题。太赫兹电磁辐射具有许多独特的性质,太赫兹时域光谱（THz-TDS）技术已发展成为一种重要的无损检测方法。文章利用太赫兹时域光谱技术,对木糖醇和D-木糖进行了光谱测量,结果表明在0.3～2.6THz波段内,木糖醇在1.62,1.87和2.51THz三个频率位置处出现吸收峰,而D-木糖的吸收峰位于1.67,1.96和2.46THz。应用密度泛函理论,对两种样品的单分子结构进行几何优化和频率计算,并据此对实验测量的吸收峰进行了指认,说明部分吸收峰源于单分子的振动模式,另一部分源于分子间相互作用的振动模式。

英文摘要：

In the present paper,THz spectra of xylitol and D-xylose are measured at room temperature in the frequency region of 0.3~2.6 THz.The results show that characteristic absorption peak of D-xylose was found at 1.67,1.96 and 2.46 THz,and those of xylitol at 1.62,1.87 and 2.51 THz.At the same time,density functional theory was applied to obtain the structure and vibration frequencies of the single molecules of two samples in THz region.The simulation results reveal that some of the absorption peaks result from the intra-molecular modes,while the others have to be attributed to intermolecular interaction or phonon modes.