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利用太赫兹时域光谱技术(THz-TDS)对两种常用的卫生杀虫剂除虫脲和高效氯氟氰菊酯在室温(298K)和低温(90K)下进行了光谱测量与分析。实验观察到两种物质存在各自明显的特征吸收峰,可将其作为太赫兹波段的指纹谱用于物质分子识别。低温与室温的太赫兹谱相比无论特征峰频率或特征峰强度都有明显的差别,蓝移和红移现象同时存在,并且低温下的特征吸收强度显著增强。为进一步理解太赫兹光谱振动吸收特性,利用CRYSTAL09软件完成了晶体的密度泛函理论模拟,其模拟结果预测出了两种物质的所有吸收峰。
Spectral measurements and analyzes of two commonly used insecticides diflubenzuron and lambda-cyhalothrin at room temperature (298K) and low temperature (90K) were performed using terahertz time-domain spectroscopy (THz-TDS). It is observed experimentally that each of the two substances has its own distinct characteristic absorption peak and can be used as a fingerprint spectrum of the terahertz band for identification of substance molecules. Compared with terahertz spectra at room temperature and low temperature, there is a significant difference in the frequency of the characteristic peaks or the intensity of the characteristic peaks. Both the blue shift and the redshift phenomena exist simultaneously, and the characteristic absorption intensity at low temperature is significantly enhanced. In order to further understand the vibration absorption characteristics of the terahertz spectrum, the density functional theory (DFT) simulation of the crystal was completed by CRYSTAL09 software. The simulation results predicted all the absorption peaks of the two materials.