Second-order nonlinear optical properties of Λ-shaped pyrazine derivatives
Second-order nonlinear optical properties of Λ-shaped pyrazine derivatives
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DOI：
10.1016/j.dyepig.2020.108850
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发表时间：
2021-01-01
影响因子：
4.5
通讯作者：
Champagne, Benoit
中科院分区：
文献类型：
--
作者：
Castet, Frederic;Gillet, Adrien;Champagne, Benoit
通过紫外/可见光和超瑞利散射光谱研究了一系列含有 4,5-二氰基吡嗪受体单元、N,N-二甲氨基供体基团和系统放大的 π 共轭连接体的 A 形衍生物的线性和非线性光学 (NLO) 性质。还进行了密度泛函理论计算，以使 NLO 响应的幅度和对称性合理化。结果表明，这些化合物具有两个能量彼此接近的低位激发电子态，这可以通过分别垂直和平行于二重分子轴偏振的单光子光学跃迁来实现。这两种状态对第一个超极化性有额外的贡献，它表现出主导的偶极特性。我们还表明 NLO 响应显着偏离克莱曼指数排列对称性。
The linear and nonlinear optical (NLO) properties of a series of A-shaped derivatives containing a 4,5-dicyanopyrazine acceptor unit, N,N-dimethylamino donor groups and systematically enlarged pi-conjugated linkers are investigated by means of UV/Visible and Hyper-Rayleigh scattering spectroscopies. Density functional theory calculations are also carried out to rationalize the magnitude and symmetry of the NLO responses. The results demonstrate that these compounds possess two low-lying excited electronic states close to each other in energy, which are accessible through one-photon optical transitions respectively polarized perpendicular and parallel to the two-fold molecular axis. These two states contribute additively to the first hyperpolarizability, which exhibits a dominant dipolar character. We also show that the NLO responses significantly deviate from Kleinman's index permutation symmetry.