Nonlinear Optics of Chained-Chromophore Polymer

链状发色团聚合物的非线性光学

• 批准号: 12650878
• 负责人: KAWAUCHI Susumu
• 金额: $ 0.9万
• 依托单位: Tokyo Institute of Technology
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2000
• 资助国家: 日本
• 起止时间: 2000 至 2001
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-12650878/
• 关键词: Nonlinear optics; Quantum chemical calculation; Molecular dynamics; Ferroelectric liquid crystal; Polyester; Polymeric liquid crystal

Organic materials with high nonlinear optics (NLO) property tend to absorb visible light. This is a deficiency because they absorb second harmonic generated (SHG) light by themselves. Main aim of this project is to design novel liquid crystalline polymers (LCP) having high NLO property without such deficiency by using quantum chemical calculations and molecular dynamics (MD) calculations.(1) The internal rotation of the ester linkage for phenyl benzoate (PB) and p-hydroxybenzoic acid (HBA) dimer (HB) as models of aromatic polyesters was investigated by using the density functional theory. The rotation of S bond, which mainly determines the linearity of the molecule, leads to the trans- and cis-conformers of PB. Since the cis-conformer of PB is 7.69 kcal mol^<-1> higher than the trans-conformer, the cis-conformer has little population at standard condition. HB does not have the cis-conformer. These agree with the experimental understanding that poly(p-hydroxybenzoic acid) is the class o … More f stiff and extended polymer.(2) The aromatic copolyester of HBA and 6-hydroxy-2-naphtoic acid (HNA) shows strong SHG-activity in the nematic phase as well as the crystalline phase in spite of no absorption in the visible region. Quantum chemistry calculations show that the second-order hyperpolarizability of the HBA dimer is comparable to that of p-nitroaniline and it increases with the degree of polymerization. The large hyperpolarizability of the aromatic polyester is ascribed to the large electronic transition moment.(3) The most stable molecular packing systems of aromatic polyester have been investigated by MD simulations performed for decamer (ten repeating units) of HBA in the nematic phase. The MD simulations were started from eight possible packing structures. Among them, we found the polar ordering structure with the intermolecular ester carbonyl groups aligned in the same direction is energetically most favorable. This is consistent with our previous experimental observation for the SHG intensity measurement. Less

具有高非线性光学(NLO)特性的有机材料往往会吸收可见光。这是一个缺陷，因为它们吸收了自己产生的二次谐波(SHG)光。本项目的主要目的是通过量子化学计算和分子动力学(MD)计算来设计具有高非线性光学性能的新型液晶聚合物(LCP)。(1)用密度泛函理论研究了苯甲酸苯酯(PB)和对羟基苯甲酸(HBA)二聚体(HB)作为芳香族聚酯模型的酯键的内转动。S键的转动主要决定了分子的线性度，导致了PB的反式和顺式构象。由于PB的顺式构象比反式构象高7.69千卡·摩尔~(-1)，所以在标准条件下，顺式构象几乎没有布居。Hb没有顺式构象。这与实验上认为聚对羟基苯甲酸是…类的理解是一致的。(2)HBA与6-羟基-2-萘甲酸(HNA)的芳香族共聚酯在向列相和晶相均表现出较强的倍频活性，但在可见光区无吸收。量子化学计算表明，HBA二聚体的二阶超极化率与对硝基苯胺相当，且随聚合度的增加而增大。芳香族聚酯的高超极化率归因于大的电子跃迁矩。(3)对十个重复单元的十聚体HBA在向列相中的分子堆积体系进行了MD模拟。分子动力学模拟从八种可能的堆积结构开始。其中，分子间酯基具有相同方向排列的极性有序结构在能量上是最有利的。这与我们之前对倍频强度测量的实验观测是一致的。较少

项目成果

T.Imase, S.Kawauchi, J.Watanabe: "Ab Initio Study of Substituent Effect on SHG-Activity of Aromatic Esters"Nonlinear Optics. 26. 91-98 (2000)

T.Imase、S.Kawauchi、J.Watanabe：“从头开始研究取代基对芳香酯 SHG 活性的影响”非线性光学。

T. Imase, S. Kawauchi, and J. Watanabe: "conformational Analysis of 1,3-Benzenediol Dibenzoate as a Model of Banana-Shaped Molecules Forming Chiral Smectic Phases"Journal of Molecular Structure. 560. 275-281 (2001)

T. Imase、S. Kawauchi 和 J. Watanabe：“作为形成手性近晶相的香蕉形分子模型的 1,3-苯二酚二苯甲酸酯的构象分析”《分子结构杂志》。

T.Imase, S.Kawauchi, J.Watanabe: "Internal Rotation of Ester Linkage in Phenyl Benzoate and Hydroxybenzoic Acid Dimer as Models of Aromatic Polyesters using Density Functional Theory"Macromolecular Theory and Simulations. 10. 434-440 (2001)

T.Imase、S.Kawauchi、J.Watanabe：“使用密度泛函理论作为芳香族聚酯模型的苯甲酸苯酯和羟基苯甲酸二聚体中酯键的内旋转”大分子理论和模拟。

T.Imase, S.Kawauchi, J.Watanabe: "Molecular Modeling of Polar Rod-Like Aromatic Polyester Forming Nematic Liquid Crystal. Part1. Ab Initio Study of Origin of Strong SHG-Activity"Molecular Crystals and Liquid Crystals. 346. 107-115 (2000)

T.Imase、S.Kawauchi、J.Watanabe：“形成向列液晶的极棒状芳香族聚酯的分子模型。第 1 部分。强 SHG 活性起源的从头研究”分子晶体和液晶。

T. Imase, S. Kawauchi, and J. Watanabe: "Molecular Modeling of Polar Rod-Like Aromatic Polyester Forming Nematic Liquid Crystal. Part1. As Initio Study of Origin of Strong SHG-Activity"Molecular Crystals and Liquid Crystals. 346. 107-115 (2000)

T. Imase、S. Kawauchi 和 J. Watanabe：“形成向列液晶的极棒状芳香族聚酯的分子模型。第 1 部分。强 SHG 活性起源的初始研究”分子晶体和液晶。