对异丙威、速灭威和抗蚜威三种常用的氨基甲酸酯类农药的荧光光谱进行了理论研究。采用密度泛函(DFT)方法,在B3LYP/6-31G水平下,对化合物的几何构型进行了全参数优化。经振动分析,均未出现虚频率,说明优化所得到的构型是势能面上的稳定点。在此基础上,采用组态相互作用(CI)方法在溶剂化效应PCM模型下计算了荧光光谱,所得结果与实验值基本吻合。计算结果表明:三种农药分子具有较强的共面性,为超共轭体系。随着供电子基团的加入,荧光光谱的波长增长,谱线发生红移。此外,取代烷基的加入对分子的荧光光谱影响较小,而胺基的加入对分子荧光光谱影响较大。
In the present paper,the fluorescence spectra of three common pesticides,isoprocarb,metolcarb and pirimicarb,were theoretically studied.The geometries of these compounds were fully optimized by density function theory(DFT) method at the B3LYP/6-31+G level.The three compounds under study were confirmed as true minima on the potential energy surface in the presence of only real frequencies by the vibrational analysis.The fluorescence spectra were calculated by configuration interaction(CI) method with PCM model,and the results match with the experimental values.The results of calculation suggest that the three compounds with planar structures are hyperconjugation systems.By the addition of the donor-electron groups,the wavelengths of the fluorescence spectra increased,and the frequencies underwent red-shift.In addition,the substitute alkyl has no more influence on the fluorescence spectra,but the addition of amido groups has more influence on the fluorescence spectra.