【摘要】 在B3LYP/6-311G(d,p)水平下优化了3种香豆素衍生物的几何构型,并通过振动分析验证了其构型稳定性。在此基础上进行垂直激发的TD-DFT(含时密度泛涵)计算,得到化合物的吸收光谱数据,然后放松激发态结构,进行TD-DFT几何优化得到化合物的荧光发射光谱。研究结果表明:3种化合物结构共平面性较好,均为较大共轭π键体系,均具有荧光特征;由于重原子效应导致化合物L-3的荧光强度相对减弱,但荧光波长变长,谱线红移;相对于吸收光谱,发射光谱均存在stokes位移,且发射光谱与吸收光谱第一吸收带之间呈镜像关系。最后,吸收光谱与发射光谱理论计算值与实验数据基本吻合表明该理论计算方法比较可靠。更多还原

【Abstract】 The 3 kinds of coumarin derivatives were optimized at the B3LYP/6-311G(D,P) level,on this basis,absorbed spectra data of the compounds were calculated by the vertical excitation of the TD-DFT(time dependent density functional calculations),and then relaxed excited state structure,compounds fluorescence emission spectra were calculated by geometry optimize of TD-DFT.The results show that:the 3 kinds of compounds,a large conjugated system,is preferably coplanar structure,and has the fluorescence characteristics;due to the heavy atom effect to result that fluorescence intensity of the compound L-3 were relatively weak,but the fluorescence wavelength,spectral line red shift;relative to the absorption spectra,emission spectra shows Stokes displacement,and the emission and absorption spectra were a mirror image relationship between the first absorption band.Finally,absorption spectra and emission spectra calculated values are consistent with the experimental value,which shows the theoretical calculation method is reliable.更多还原