卟啉-碳硼烷-硼亚甲基二吡咯三元化合物二阶非线性光学性质的理论研究

Theoretical Study on the Second-order Nonlinear Optical Properties of a Porphyrin-o-Carborane-Boron-dipyrromethene Triad Compound

采用密度泛函理论(DFT)方法对卟啉-碳硼烷-硼亚甲基二吡咯(BODIPY)三元化合物的几何结构、吸收光谱及二阶非线性光学(NLO)特性进行计算分析.结果表明,V型化合物的静态第一超极化率(βtot)大于相应直线型化合物,且延长共轭链可提高体系的βtot.分析体系的电子密度差分图得出,化合物氧化还原态的电荷转移方式与本征态相比发生了改变,从而使其二阶NLO性质发生明显变化.含频第一超极化率计算结果表明,在一定范围内频率对化合物有较小的色散效应.因此,通过延长二维化合物的共轭链及氧化还原反应,可以有效调控其二阶NLO响应.

The calculations of geometric structures,electronic absorption spectra,second-order nonlinear optical(NLO) properties of porphyrin-o-carborane-boron-dipyrromethene(BODIPY) triad were carried out by density functional theory(DFT). The results show that the static first hyperpolarizability(βtot) of the V-shaped compound is larger than that of the linear-shaped compound,and the βtotvalues can be enhanced by extendingπ-conjugate bridge. The analysis of electron density difference maps can be seen that the charge transfer pattern of the oxidized/reduced species have changed,which lead to the second-order NLO properties have significantly varied. The investigation of the frequency-dependent first hyperpolarizability shown that less dispersion effect at restrictive frequency region for all of the compounds. Therefore,second-order NLO properties can be effectively modulated by extending π-conjugate bridge and oxidized/reduced reactions.