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1.
The autocorrelation function is an important quantity that can reflect the dynamical properties of the Rydberg wave packet and can be measured in experiments. Applying time-dependent perturbation theory and rotating wave approximation, we derive the autocorrelation function of the double-pulse laser describing the evolution of a Rydberg wave packet of hydrogen atoms in magnetic fields. The resulting expression is written as a sum of the modified Caussian terms. Each Caussian term comes from a parent semiclassical closed orbit. It provides a direct explanation and experimentally controllable measurement scheme, which allows us therefore to recognize the closed orbit and to determine its returning time in high precision. 相似文献
2.
具有C2对称轴的手性配体及其不对称催化反应 总被引:2,自引:0,他引:2
按配位原子的数目进行分类,综述了近年来研究较多的具有C2对称轴的手性配体及其相关的不对称催化反应,并对该类手性配体的设计做了分析和总结。参考文献79篇。 相似文献
3.
铬(Ⅵ)与谷胱甘肽作用及其中间态配合物形成的电化学表征 总被引:2,自引:0,他引:2
本文采用电化学方法,对谷胱甘肽(GSH)与重铬酸钾的相互作用及其中间态配合物的形成过程进行研究。结果表明:在pH=5.6的HAc-NaAc缓冲溶液中,GSH浓度为Cr(Ⅵ)浓度5倍以上时,Cr(Ⅵ)与GSH作用完全并形成一新的中间态配合物,该中间态配合物于+0.21 V和+0.36 V(vs SCE)处产生一对新的氧化还原峰,UV-Vis的吸收光谱进一步证明了中间态配合物的形成。该配合物不稳定,在一定时间内缓慢分解,其电化学与UV-Vis光谱动力学信息同步。进一步探讨了GSH与Cr(Ⅵ)作用的电极反应机理。当Zn(Ⅱ)存在于该体系时,Zn(Ⅱ)对中间态配合物的生成和分解过程起着双向催化作用。 相似文献
4.
A one-pot procedure for the efficient synthesis of a small library of t-RNA inhibitor analogues was developed. Thus,Rh2(OAc)4 catalyzed three-component 1,3-dipolar cycloaddition reactions of carbonyl ylides derived from diazoindan-1,3-dione and aldehydes with other dipolarophiles in 1,1,2,2-tetrachloroethane at 80 ℃ gave ring fused tetrahydrofurans having three stereocenters in good yield. 相似文献
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Two series 3-armed dendritic molecules with their 1,3,5-tris(4-methyloxyphenyl) benzene or 2,4,6-tris(4- hydroxylphenyl)-1,3,5-s-triazine core and triphenylene derivative shells connected by soft hydrocarbon chains have been synthesised and fully characterised. Whether liquid crystal (LC) or photoluminescence materials have been tuned by changing the length of the soft chain and they have been studied by POM, DSC, XRD, UV-Vis and PL. The results show that all the new dendritic compounds display UV to blue fluorescence in solvents such as DCM, THF and acetone. The TC3 compound bearing 1,3,5-tris(4-hydroxylphenyl) benzene core exhibits LC property with rectangular columnar phase (Colr) on cooling. 相似文献
9.
Chin-Kuen Tai Pao-Ling Yeh Chun-Chi Chang Wen-Hao Chen Rong-Hou Wu Yu-Ma Chou Bo-Cheng Wang 《Research on Chemical Intermediates》2014,40(6):2355-2362
Recently, the organic synthesis and electronic device applications of π-conjugated polymer-based materials with low energy band gap (below 2 eV) and high values of incident photon to current efficiency have been presented. In the present study, the physical properties of polythiophene (PTH) and its derivative systems (PTs) were investigated as π-conjugated low energy band gap polymers. Density functional theory with periodic boundary condition (PBC), the B3LYP functional, and the 6-31G(d) basis set was applied to determine their geometric and electronic structures and corresponding energies (E HOMO, E LUMO, and E g = E LUMO ? E HOMO) from the monomer of thiophene and its derivatives for one-dimensional (1D) extension to polymer. The effects of 3-substitution in PTs including electron-donating (CH3–, C6H13–, OH–, Cl–, OCH3–, and CHO–) and electron-withdrawing groups (Cl–, CHO–, CN–, NO2–, CF3–, and COOH–) compared with PTH were investigated. According to the calculation results, PTs with electron-donating and electron-withdrawing substituents should exhibit red- and blue-shifts, respectively, compared with PTH. These calculation results show good agreement with experimental data and provide further information for molecular design considerations. 相似文献
10.
报道含亚胺和胆甾烯基不对称液晶二聚体化合物XC6H4N=CHC6H4OC10H20COOCh* [X=OCnH2n+1, (n=1~12,14), F, Cl, Br, CH3] (1a~1q)的合成及液晶性. 目标化合物通过600 MHz 1H NMR和元素分析进行了结构表征. 其介晶性通过偏光显微镜(POM)和差示扫描量热计(DSC)进行了研究. 结果显示: 所有化合物都具有胆甾相(N*). 对于烷氧基系列(X=OCnH2n+1), 有部分化合物还呈现了近晶A相(SA), 且随着末端烷氧链长度的增加, 化合物的清亮点呈现缓慢下降的趋势, 而化合物从胆甾相到各向同性液体转变的熵变(ΔSN*→I)则呈现奇-偶效应. 同时我们对比研究了取代基X对胆甾相稳定性的影响, 发现取代基X对胆甾相的稳定性高低顺序为: MeO>Cl>Br>Me>F. 这些结果证实了末端取代基的改变对化合物的相转变温度以及介晶性质有显著的影响. 相似文献