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含1,3-方酸苯螺旋共轭分子的设计及其电子光谱和非线性光学性质的理论研究 总被引:9,自引:0,他引:9
以量子化学半经验方法PM3优化构型为基础,利用INDO/CI方法研究了嵌入1,3-方酸的苯螺旋共轭分子的电子光谱。同时利用INDO/CI-SOS程度计算了它们的二阶非线性光学系数βijk和βμ值,从而探索分子结构与电子光谱及非线性光学性质的关系。理论计算结果表明:在苯螺旋共轭分子中适当地嵌入方酸后,其二阶非线性光学系数增大,与苯螺旋共轭分子和1,3-方酸的比较表明,方酸环处于左端的体系有很好的二阶非线性光学性质,可能成为较好的光学材料。 相似文献
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采用PM3和INDO/CI理论方法,系统研究了对称取代反式二苯乙烯衍生物的结构和电子光谱。在正确的UV-Vis光谱基础上,预测了双光子吸收峰的位置。自编程序用SOS公式计算了三阶非线性光学系数及双光子吸收截面,并从微观上探讨了不同取代基对双光子吸收截面的影响。 相似文献
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应用量子化学AM1半经验方法分别对巴比妥酸及硫代巴比妥酸的葡萄糖基系列取代衍生物B1-5和T1-5进行几何优化。基于优化后的稳定构型,利用INDO/CI方法计算其电子光谱。同时,根据完全态求和(SOS)公式计算其二阶非线性光学系数。结果显示,当葡萄糖基单元数增加时,无论是巴比妥酸衍生物还是硫代巴比妥酸衍生物,|βμ| 均增大,尤其是硫代巴比妥酸衍生物增大更为显著,表明此种非共轭取代基同样可以改善材料的非线性光学性质。此外,随葡萄糖基链增长时,光谱的变化并不十分显著,且由于所有吸收带均在紫外光区内,因此推测所有体系均有望成为具有高度透明性的非线性光学侯选材料。 相似文献
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在INDO/CI方法基础上, 用自己编制的计算二阶非线性极化系数β_(ijk)程序, 计算了苯胺、硝基苯、对硝基苯胺和4-硝基-4′-胺基二苯乙烯的β_(ijk), 并研究了其对外部激光场频率的依赖关系。结果表明, 分子内的电荷转移是产生非线性光学现象的根本原因, 而作为外因的激光场对二阶非线性光学系数的大小和方向也有直接的重要作用。当激光场频率与分子的共振频率接近时, 二阶非线性极化系数变得非常大, 在共振频率附近, β_(ijk)改变符号且Kleinman对称性被打破。 相似文献
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F. G. Baddar M. H. Nosseir G. G. Gabra N. E. Ikladious 《Journal of polymer science. Part A, Polymer chemistry》1971,9(7):1947-1958
A kinetic study of the polyesterification reaction of γ-phenyl- γ-p-methoxyphenyl-, and γ-p-chlorophenylitaconic acids (1 mole) with ethylene glycol in the presence or in absence of p-toluenesulfonic acid as a catalyst has been carried out in order to show the effect of substituents on the rate and degree of polymerization. The reaction of 1 mole of the acid and an excess of ethylene glycol has also been studied. In all cases the reaction is found to follow the second-order rate equation. The mechanism of polyesterification has been discussed. In catalyzed polyesterification electron-withdrawing groups (CI) decrease the velocity of the reaction. The low values of ρ in both the auto-catalyzed and catalyzed reaction indicate that this polyesterification is slightly sensitive to the polar nature of the substituent. 相似文献
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The equilibrium geometry and UV-visible spectra of C70 were examined using semiempirical INDO /2 and INDO /CI methods. The results obtained are in good accord with experimental results. On the basis of correct electronic spectra, calculations of the nonlinear third-order optical susceptibility (γijkl) of C70 were performed using the INDO /SDCI method combined with a sum-over-states expression. The calculated value for <γ> (-2 ω, ω, ω, O) is 0.882 × 10?33 esu (ω = 1.91 μm), which is in good agreement with observation. © 1994 John Wiley & Sons, Inc. 相似文献
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Hans R. Kricheldorf Sharda V. Joshi William E. Hull 《Journal of polymer science. Part A, Polymer chemistry》1982,20(10):2791-2807
Alternating copolyamides of various ω-amino acids were synthesized by base-catalyzed polycondensation of N-isothiocyanatoacyl ω-amino acids in solution. Derivatives of the following amino acids were used: glycine, β-alanine, γ-aminobutyric acid, δ-aminovaleric acid, ε-aminocaproic acid, D ,L -β-aminobutyric acid, trans-4-aminocyclohexane 1-carboxylic acid, 4-aminophenyl acetic acid, 3-aminobenzoic acid, 4-aminobenzoic acid, 3-amino-4-methyl benzoic acid, and 4-amino-3-methyl benzoic acid. The base-catalyzed polycondensation at lower temperatures gave purer products than the bulk condensation at 180–200°C. 13C-NMR and natural-abundance 15N-NMR spectra measured in trifluoroacetic acid demonstrate that in most cases undisturbed alternating sequences were obtained. Strong neighboring residue effects and long-range sequence effects were found in the 15N-NMR spectra, and structure/shift relationships are discussed. The sequences of copolyamides obtained by copolymerizations of lactams or β-amino acid N-carboxyanhydrides were investigated by both 15N-NMR and 13C-NMR spectroscopy. 13C-NMR spectroscopy was found to be more useful if the copolyamides consist of ω-amino acid units of different chain length. However, 15N-NMR spectroscopy is more suited if the monomer units differ exclusively by their substituents. 相似文献
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Hiroshi Mitsui Fumio Hosoi Miyuki Hagiwara Tsutomu Kagiya 《Journal of polymer science. Part A, Polymer chemistry》1968,6(10):2881-2888
The effects of acetylene on the γ-radiation-induced polymerization of ethylene were studied from the viewpoint of the gaseous products and polymer structure. The experiments were carried out under a pressure of 400 kg/cm2; the temperature was 30°C; the does rate was 1.1 × 105 rad/hr; and the acetylene content was 0–20%. The solid polymer was obtained in the polymerization of ethylene containing 2.2% acetylene, while the monomer containing 19.7% acetylene gave a yellowish viscous oil. The polymer yield and molecular weight decreased remarkably with acetylene content. The main gaseous product was hydrogen, and trace amounts of butane, butene-1, butadiene-1,3, and benzene and its derivatives were also observed. The rate of formation of hydrogen was almost independent of acetylene content and there was no difference in acetylene contents before and after the irradiation was found. The infrared spectra of the polymers showed the presence of vinylidene, trans-vinylene, and terminal vinyl unsaturations, 1,4-disubstituted benzene, and carbonyl groups. The contents of trans-vinylene, terminal vinyl, and methyl groups increased with acetylene content, and that of vinylidene was independent of acetylene content. The monomer reactivity ratios of ethylene and acetylene were evaluated as 45.5 and 66.0, respectively. On the basis of the results, the effects of acetylene on the γ-radiation-induced polymerization of ethylene were discussed. 相似文献