有机半导体ADN的DFT理论计算研究

采用密度泛函理论(DFT)方法对9,10-二(2-萘基)蒽(ADN)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、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ADN在0.1～10 THz波谱范围内有5个明显的吸收峰,分别位于1.08、2.52、4.44、5.64及6.60 THz,其中5.64 THz的吸收是最强的,它是由萘环面外弯曲及蒽环面内摇摆振动产生的。ADN在紫外光波段有三个吸收峰,分别对应于386.34、352.98及352.50nm,其中386.34 nm的紫外吸收峰最强。ADN理论计算能隙值为3.516 eV,比实验值3.2 eV略高。ADN的Mulliken电荷计算表明,所有H原子的Mulliken电荷皆为正电荷,C原子Mulliken电荷与其具体的化学环境相关。

The Study on Organic Semiconductor ADN by DFT Theoretical Calculation

The geometry optimization, IR spectrum, Raman spectrum, UV-Vis spectrum, frontier molecular orbitals as well as Mulliken charges calculations on 9,10-Di(2-Naphthyl)Anthracene (ADN) are performed by using Density Functional Theory (DFT) at B3LYP/6-31G level. Research results show that the theoretical calculation results agree well with experimental data, the characteristic peaks in IR, THz, UV-Vis and Raman spectra have been assigned. It is found that in 0.1～10 THz range ADN has five obvious absorption peaks which locate at 1.08, 2.52, 4.44, 5.64 and 6.60 THz，respectively. Among them, the strongest absorption peak locates at 5.64 THz that is caused by the out-of-plane bending of naphthalene ring coupled with the in-plane rocking of anthracene ring. In the UV-Vis spectrum ADN has three absorption peaks centered at 386.34,352.98 and 352.50 nm，among them the strongest peak is 386.34 nm. The theoretical calculated energy gap is 3.516eV, which is slightly bigger than that of experimental value (3.2 eV). The Mulliken charges calculation indicates that all the H atoms charge positive Mulliken charges, and the Mulliken charges of C atoms are relevant to their chemical environments.