三聚咔唑为中心的准八极矩分子二阶NLO性质

采用密度泛函理论B3LYP/6-31G*方法,对一系列以三聚咔唑为中心核的准八极矩分子的几何结构进行优化,在所得优化结构的基础上,结合有限场方法(FF)和含时密度泛函理论(TD-DFT)探讨了体系的二阶非线性光学(NLO)性质和电子光谱。结果表明,研究分子的极化率(α)及二阶NLO系数(β)随着取代基吸电子能力的增强而增大。当研究分子以三氰基苯乙烯为受体,碳-碳双键为共轭桥时,显示了较大的二阶NLO系数和良好透光性的优化,说明准八极矩分子内多重电荷转移可以有效地解决"非线性-透光性"矛盾。该系列分子在非线性材料领域中有望成为具有良好应用价值的候选分子。

Second-order nonlinear opticalproperties of triindole-cored pseudooctupolar molecules

Density functional theory(DFT)B3LYP/6-31G*method was used to optimize the geometrical structures of a series of triindole-cored pseudo octupolar molecules.On the basis of obtained stable molecular configuration,the nonlinear optical(NLO)properties and electronic spectra were then studied by finite field(FF)and time-dependent DFT(TD-DFT)at the same level.It can be shown that the polarizability α,second-order NLO coefficient β of the molecules increase with increasing of electron-acceptor ability of the substituent groups.The molecule with tricyanostyrene acceptor and C=C double bond conjugated bridge would exhibit the optimization of the large second-order NLO coefficient and good transparency in research systems.The"nonlinear-transparency tradeoff"conflict is effectively solved because of the multiple charge transfers of pseudo octupolar molecules.These pseudo octupolar molecules might become candidates in the development of NLO materials.