有机半导体Butyl-PBD的DFT理论计算研究

The Study on Organic Semiconductor Butyl-PBD by DFT Theoretical Calculation

采用密度泛函理论(DFT)方法对2-(4-叔丁苯基)-5-(4-联苯基)-1,3,4-恶二唑(Butyl-PBD)进行了B3LYP/6-31G水平上的分子结构优化、红外光谱、Raman光谱、紫外-可见光谱、分子前线轨道、分子电子密度、Mulliken电荷等理论计算。研究结果表明:理论计算结果与实验数据吻合得较好,对IR、THz、UV-Vis吸收光谱和Raman散射光谱中的特征峰进行了归属,发现Butyl-PBD在0.1～10 THz波谱范围内有五个明显的吸收峰,分别位于2.04 THz、3.48 THz、5.16 THz、6.60 THz及7.08 THz,Butyl-PBD在紫外光波段有三个吸收波段,分别对应于326.76 nm、279.60 nm及269.31 nm,其中326.76nm的紫外吸收峰最强。电子密度计算表明,最大电子密度集中在O原子上,N原子的电子密度次之。Mulliken电荷计算表明,负电荷主要集中在O原子和N原子上,所有H原子的Mulliken电荷都为正电荷,C原子的Mulliken电荷则与其具体位置相关。

The geometry optimization,IR spectrum,Raman spectrum,UV-Vis spectrum,frontier molecular orbitals,electron density as well as Mulliken charges calculations on 2-（4-tert-Butylphenyl）-5-（4-phenylphenyl）-1,3,4-oxadiazole（Butyl-PBD） are carried out by using Density Functional Theory（DFT） at B3LYP/6-31G level.Research results show that the theoretical calculation results agree with experimental data well,and the characteristic peaks in IR,THz,UV-Vis and Raman spectra have been assigned.It is found that Butyl-PBD has five obvious absorption peaks in 0.1～10 THz range,which are located at 2.04,3.48,5.16,6.60 and 7.08 THz,respectively.Butyl-PBD has three UV-Vis absorption bands centered at 326.76,279.60 and 269.31 nm,and among them,the strongest peak is 326.76 nm.The electron density calculation shows that the most electron density focuses on O atom,followed by N.The Mulliken charges calculation indicates that negative charges are mostly located at O and N atoms,all the Mulliken charges of H atoms are positive,and the Mulliken charges of C atoms are relevant to their chemical environments.