系列金化合物[X-{Au(PMe_3)}_2]的结构、电子光谱和非线性光学性质

Theoretical investigation on structures,electronic spectra and nonlinear optical properties of gold compounds [X-{Au(PMe_3)}_2]

采用密度泛函理论(DFT)B3LYP和BhandHLYP方法,对6个不同金化合物[X-{Au(PMe3)}2]的几何结构、电子光谱以及极化率和三阶非线性光学(NLO)效应进行了计算分析.本文采用的计算方法和基组适合所研究的对象,并发现用PMe3代替PPh3对分子整体结构影响不大.另外,分子桥连部分的空间效应对极化率有明显影响,对三阶极化率影响却不大.关于6个分子的三阶NLO性质,由于X部分的电子性质及共轭程度不同,分子1a的三阶极化率γ值最小,分子2a的γ值最大.通过分析电子光谱和对应的分子轨道组成可知,Au在分子1a中做电子给体,而在分子2a～6a中做电子受体,表明Au在此类化合物中对NLO性质的贡献不同.

The structures,electronic spectra,polarizability and third-order nonlinear optical properties of six gold compounds [X-{Au（PMe3）}2] were investigated by density functional theory （DFT） B3LYP and BhandHLYP methods. It was found that the calculation methods and basis set are rational for the object of study,and molecular structures change slightly when PPh3 is replaced by PMe3. The spatial effects of the bridging section have a significant influence on the polarizability,but indistinctive to the third-order nonlinear optical （NLO） coefficient. As a result of the conjugated effect in different compounds,the third-order polarizability of molecule 1a is the smallest,while that of molecule 2a is the largest. Au has donor ability in molecule 1a but acceptor ability in molecules 2a–6a by analyzing the electronic spectra and frontier molecular orbitals constitute maximal absorption,which indicates the contribution of Au to NLO properties in the six molecules is different.