乙草胺的拉曼光谱计算及分析

Raman Spectra Calculation and Analysis of Acetohlor

乙草胺是我国广泛使用的除草剂之一,其本身及其代谢物对人体都有潜在的危害,通过鉴别乙草胺分子的振动信息,能够直接识别植物中乙草胺成分。本文在理论上,分别利用密度泛函理论(DFT)中的三参数杂化泛函B3LYP以及Hartree-Fock(HF)两种算法,所选用基组皆为6-311G++(d,p),对乙草胺分子进行了结构优化以及拉曼光谱计算,以得到乙草胺分子的振动信息。从结果中显示,由于计算方法不同,两种方法计算得出的峰位略所不同。在实验上,利用PI公司的TriVista555CRS型三级联光栅共聚焦显微拉曼光谱仪测得乙草胺原药的拉曼光谱。实验所得的拉曼光谱严重受到荧光峰的干扰,使得线型上与理论计算结果差异较大,针对此问题,对实验拉曼光谱进行了去荧光处理。并针对理论结果在频率上存在的误差,使用修正因子对两种方法分别进行了修正。经以上步骤处理后,发现实验结果与理论计算结果基本吻合,进而对500~3300cm-1区间的振动光谱进行了指认。本文的工作为乙草胺的残留检测提供了理论基础。

Acetochlor is one of the most used herbicides in China.Its metabolites and itself both have potential harm to the human body.It can be distinguished from plants by identifying its vibration information.In this article,the structure of acetochlor was optimized and its Raman spectrum was calculated with the three-parameter hybrid functional B3LYP of the density functional theory(DFT) and the Hartree-Fock(HF) algorithm respectively both based on the 6-311G++(d,p) level to obtain the vibration information in theory.As is shown in the calculation results,the peak positions calculated are slightly different for the different methods.The Raman spectrum of the analytical reagent of acetochlor was collected by the three-stage grating confocal micro-Raman spectrometer-TriVista 555CRS produced by PI company in experiment.The experimental Raman spectrum is seriously interfered by the fluorescence peaks,which makes the difference of linear type between the experimental result and the theoretical calculation result.For this problem,we have the experimental Raman spectrum defluorinated.And for the error of the theoretical result in frequency,the correction factors are used to correct the two methods.After the above steps,it was shown that the experimental result were basically consistent with the theoretical calculation result,that the vibrational spectra of the 500~3300 cm -1 interval were assigned.The work of this paper provides a theoretical basis for the residue detection of acetochlor.