摘要
采用密度泛函理论(DFT)CAM-B3LYP方法对6,12-二乙炔基茚并[1,2-b]芴系列衍生物的极化率(αs)和第二超极化率(γs)进行研究.结果表明,此类分子具有较大的γs值.用乙炔基硅烷基和氧原子取代茚并[1,2-b]芴分子6,12位的氢原子后,分子的几何构型发生改变,进而影响其非线性光学(NLO)性质.连接乙炔基硅烷基的分子αs值和γs值均增大,而连接氧原子的分子αs值和γs值均减小.茚并[1,2-b]芴环2,8位取代基R(R=H,F,CH3)的不同,对分子的γs值也有一定的影响,R为CH3时分子的αs值和γs值均较大.由含时密度泛函理论(TD-DFT)方法计算的吸收光谱分析可知,与茚并[1,2-b]芴系列分子相比,引入乙炔基硅烷基的分子共轭性增强,最大吸收波长红移;引入氧原子的分子几何结构扭曲,共轭性降低,最大吸收波长蓝移.
The polarizabilities （as） and second hyperpolarizabilities （ys） of a series of 6,12-diethynylindeno [1,2-b]fluorene derivatives were investigated by the density functional theory CAM-B3LYP method. The calculated results indicate that these molecules possess considerably large second hyperpolarizabilities. Replacing the 6,12-hydrogen atoms on indeno[1,2-b]fluorene molecules by ethynyl silyl or oxygen atoms results in a change in the geometry of the molecular structure, which affects the nonlinear optical （NLO） properties. Introducing ethynyl silyl groups into the molecules can increase the as and ys values, while these values decrease introducing oxygen atoms into the molecules. Also, the ys values depend on the 2, 8-disubstituted R groups （R=H, F, CH3） of the indeno[1,2-b]fluorene molecules. When R is methyl, the molecule has much larger as and ys values. Moreover, according to time-dependent density functional theory calculations on the indeno[1,2-b]fluorene series, the maximum absorption wavelength of the ethynyl silyl derivatives display a bathochromic shift due to increasing conjugation, while a blue shift of the maximum absorption wavelengths are observed in the oxygen-substituted derivatives because the conjugation decreases as the molecular structure is distorted.
出处
《物理化学学报》
SCIE
CAS
CSCD
北大核心
2012年第12期2839-2844,共6页
Acta Physico-Chimica Sinica
基金
国家自然科学基金(21173035)
和吉林省自然科学基金(20101154)资助项目~~
关键词
茚并[1
2-b]芴衍生物
几何构型
非线性光学性质
吸收光谱
密度泛函理论
Indeno[1,2-b]fluorene derivative
Geometric configuration
Nonlinear optical propertyAbsorption spectrum
Density functional theory
