Unraveling the Electric Field-Induced Second Harmonic Generation Responses of Stilbazolium Ion Pairs Complexes in Solution Using a Multiscale Simulation Method
Unraveling the Electric Field-Induced Second Harmonic Generation Responses of Stilbazolium Ion Pairs Complexes in Solution Using a Multiscale Simulation Method
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使用多尺度模拟方法揭示溶液中芪唑离子对配合物的电场感应二次谐波产生响应
DOI：
10.1021/acs.jcim.9b01161
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发表时间：
2020
影响因子：
5.6
通讯作者：
B. Champagne
中科院分区：
文献类型：
--
作者：
Tárcius N. Ramos;S. Canuto;B. Champagne
电场诱导二次谐波响应（EFISHG）被广泛用于描述溶液中的第一β和第二γ超极化率。虽然EFISHG技术不能应用于带电的化合物（由于外部静电场），但它可以用来描述中性复合物的离子对。一个多尺度的计算方法是必需的，以产生这种复合物的代表性的几何配置（使用经典力场），计算每个配置的电子结构（使用量子力学方法），并进行统计分析描述的非线性光学性能的行为。在这项工作中，我们的目标溶剂化中性离子对复合物，其中的阳离子是一个有机生色团，我们估计他们的EFISHG和超瑞利散射响应。结果表明，阴阳离子的相对空间分布决定了复合物的永久偶极矩，因此相对距离控制EFISHG响应。另一方面，β张量与偶极矩无关，与阳离子的π电子共轭长度呈弱的线性相关。γ在总体EFISHG响应中的贡献范围为5%至15%，主要是由于μ和β矢量方向的差异。所应用的多尺度方法提供了合理的结果与实验相比，虽然仍然需要额外的努力，以改善这种比较，主要是考虑可能的解离效应。
The electric field-induced second harmonic generation (EFISHG) response has been largely used to describe the first β and the second γ hyperpolarizabilities in solution. Although the EFISHG technique cannot be applied to charged compounds (due to the external static electric field) it can be used to describe ion pairs as neutral complexes. A multiscale computational approach is required to generate representative geometrical configurations of such kind of complexes (using classical force fields), to compute the electronic structure of each configuration (using quantum mechanics methods), and to perform statistical analyses describing the behavior of the nonlinear optical properties. In this work, we target solvated neutral ion pairs complexes, of which the cation is an organic chromophore, and we estimate their EFISHG and hyper-Rayleigh Scattering responses. It is shown that the anion-cation relative spatial distribution determines the permanent dipole moment of the complexes and therefore the relative distance controls the EFISHG response. On the other hand, the β tensor is independent of the dipole moment and it shows a weak linear correlation with the π-electron conjugation length of the cations. The γ contributions in the global EFISHG response ranged from 5% to 15% mainly due to the differences in the μ and β vectors orientation. The applied multiscale approach provides reasonable results compared with the experiment although additional efforts are still required to improve such comparison mainly to consider the possible dissociation effects.
影响因子：
64.8
作者：
Kawata, S;Sun, HB;Takada, K
通讯作者：
Takada, K