BeQ2衍生物中金属配体间相互作用对前线分子轨道和非线性光学性质影响的理论研究

采用从头算HF及密度泛函理论(DFT)B3LYP方法对8-羟基喹啉铍(BeQ2)及其取代衍生物Be(MQ)2,Be(CNQ)2的稳定结构及结合能进行计算.在此基础上,系统分析了前线分子轨道组成及体系非线性光学系数的变化.计算结果表明,金属-配体间的相互作用使非线性光学系数增大,且γ比β增大得多;CH3和CN的推拉电子取代均使结合能降低,电子离域性增强,非线性光学性质得以改善.

Theoretical Studies on Effect of the Interaction Between Metal and Ligands on Frontier Molecular Orbitals and Nonlinear Optical Properties Within BeQ2 and Its Derivatives

The calculations of stable structures and binding energies for BeQ2 and its substituted derivatives have been performed at HF and B3LYP levels. On this basis, changes in frontier molecular orbitals as well as nonlinear optical coefficients have been analysed systematically. It is shown that the interaction between metal and ligand could increase the value of the third order NLO susceptibility γ more significantly than that of the second order NLO susceptibility β; either electrondonor CH3 or electron acceptor CN can lower the binding energy, which increases the delocalization of electrons in the calculated systems, thus can contribute to improving in NLO properties.