硝基多环芳烃类致癌污染物太赫兹光谱及其光降解特性研究

硝基多环芳烃类物质是引发肺癌的一类重要污染物。准确表征与识别此类致癌污染物，研究其在光辐照条件下的光降解特性及反应机理具有非常重要的意义。本项目通过采用稳态太赫兹时域光谱技术研究不同环境条件下该类化合物分子的特征吸收光谱，建立其在太赫兹波段下的吸收谱图库，同时建立特征光谱与分子的构型/构象、硝基取代位置和取向角度等之间的相关联系；还将利用时间分辨振动光谱技术开展硝基多环芳烃类分子体系光照后光物理和光化学过程动力学研究，获取该类分子光诱导反应过程中激发态、瞬态中间体形成与衰变以及光解反应产物振动指纹光谱和动力学信息，从而在微观水平上解释其在光辐照后相应的光降解特性及其光化学机理。这些研究结果将为今后用分子振动光谱技术快速准确探测不同种类硝基多环芳烃类致癌污染物，从分子层面上理解其生物致癌毒性能力的构-效关系、以及提出控制与清除此类致癌污染物的有效方法奠定基础。

As well-known and important pollutants, nitropolycyclic aromatic hydrocarbons (NPAHs) would lead to serious lung cancer. It is significant to recoganize and characterize such carcinogenic NPAHs accurately, and inveistigate their photodegradation mechanism upon light photolysis. In this research project, the characteristic absorption spectra of different NPAHs molecules will be collected under different conditions with steady-state terahertz time-domain spectroscopy (THz-TDS) technique. The THz absorption spectra database will be built, and the cerrelation between characteristic THz absorption spectra and the corresponding molecular conformation and the different orientation of substituted nitro-group will be elucidated according to these results. Photophysical and photochemical processes of NPAHs will be investigated using time-resolved vibrational spectroscopy, in order to determine the photodegradation mechanism from the rich information about the finger-printing spectra and kinetics of the photoinduced excited states, transient species and final photo-products. The accomplishment of this research project will provide us the benchmark evidence for detecting such NPAHs carcinogenic pollutants quickly and accurately, understanding their structure-carcinogenic activity relationship from molecular level with molecular vibrational spectroscopy, and also for developing the efficient methods to control and eliminate NPAHs in the future.