六元碳环邻位对称取代的Λ-型分子非线性光学系数的计算

采用密度泛函理论(DFT)的BHandHLYP/6-31G*方法,对3类含有六元碳环的Λ-型分子的几何构型进行优化.在优化结构的基础上,结合有限场方法(FF)和含时密度泛函理论(TD-DFT)对分子的二阶非线性光学(NLO)活性及电子吸收光谱进行研究.结果表明,在拐点处环己烷的构象不同时,分子电荷分布、偶极矩、极化率、二阶NLO系数和电子吸收光谱等变化很小.以苯环为拐点片段的分子有所不同,当支链取代基R增大时,以苯环为拐点片段分子的极化率和二阶NLO系数增加明显.

Computational Study on Nonlinear Optical Properties of Λ-Shaped Molecules with Six-membered Carboatomic Ring of Symmetrical Substituent

Density functional theory(DFT) BHandHLYP at 6-31G* level was employed to optimize the structures of three kinds of Λ-shaped molecules with six-membered carboatomic ring. On the basis of obtaining stable molecular configuration, combined with finite field(FF) method and time-dependent density-functional theory(TD-DFT), the second-order nonlinear optical(NLO) property and molecular electric spectrum were calculated. The results indicate that when the conformation of cyclohexane of inflexion is different, the charge distrbution, the dipole moment, the polarizability, the second-order NLO coefficients and the electric spectrum of molecules are slightly variational. The molecule with benzene of inflexion is different from the molecules with cyclohexane of inflexion, when the substituting group R of branched chain is increscent, the polarizability and second-order NLO coefficient are more explicitly increased.