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尿酸分子互变异构体平面构象的理论研究 被引量:7
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作者 陈文凯 陆春海 +2 位作者 许娇 杨迎春 李俊篯 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 北大核心 2002年第2期186-190,共5页
使用半经验量子化学中的AM1方法、从头计算Hartree-Fock理论(在3-21G*水平)和密度泛函理论中的B3LYP方法(使用6-31G(d)基组),研究了尿酸分子的所有35种互变异构体.计算结果表明,三羰基互变异构体是所有异构体中能量最低的,其次为单羟基... 使用半经验量子化学中的AM1方法、从头计算Hartree-Fock理论(在3-21G*水平)和密度泛函理论中的B3LYP方法(使用6-31G(d)基组),研究了尿酸分子的所有35种互变异构体.计算结果表明,三羰基互变异构体是所有异构体中能量最低的,其次为单羟基异构体和双羟基异构体,而含有三羟基的互变异构体相对能量最高.随着羟基数的增加,C-N键的平均键长从1.395?逐渐缩短到1.351?,而C-C键的平均键长基本保持不变(1.400~1.406?). 展开更多
关键词 分子互变异构 平面构象 尿酸 量子化学 分子结构 密度泛函理论
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Oxonol染料的稳态光物理行为研究
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作者 姜永才 张晓宏 吴世康 《物理化学学报》 SCIE CAS CSCD 北大核心 2004年第4期350-354,共5页
对oxonol——一种带负电荷类菁染料化合物溶液的光谱和光物理问题进行了研究。发现它和一般分子内共轭的电荷转移化合物相比,无论在吸收光谱或荧光发射光谱上,都表现出不同的光物理和光化学行为。对出现的这种差异,特别是负的溶致变色... 对oxonol——一种带负电荷类菁染料化合物溶液的光谱和光物理问题进行了研究。发现它和一般分子内共轭的电荷转移化合物相比,无论在吸收光谱或荧光发射光谱上,都表现出不同的光物理和光化学行为。对出现的这种差异,特别是负的溶致变色行为和在不同pH条件下分子的互变异构等对吸收光谱的影响进行了讨论。 展开更多
关键词 Oxonol染料 稳态光物理行为 负溶致变色行为 电子光谱 分子互变异构 感光材料 光敏剂
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晶体学辅助的2-吡啶甲酸固体13C化学位移理论计算归属(英文)
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作者 张之杰 李端秀 +3 位作者 罗春 仇汝臣 邓宗武 张海禄 《波谱学杂志》 CAS 北大核心 2020年第1期67-75,共9页
有机分子的互变异构现象在溶液中较为常见.而对于有机固体而言,存在互变异构可能的分子常以单一的能量最稳定的异构体形式存在.2-吡啶甲酸(PCA)是一个较为罕见的案例,它的晶体结构中同时存在有中性分子和两性离子两种互变异构体.由于超... 有机分子的互变异构现象在溶液中较为常见.而对于有机固体而言,存在互变异构可能的分子常以单一的能量最稳定的异构体形式存在.2-吡啶甲酸(PCA)是一个较为罕见的案例,它的晶体结构中同时存在有中性分子和两性离子两种互变异构体.由于超长的质子纵向弛豫时间,PCA的固体^13C核磁共振(NMR)实验的化学位移归属存在困难.密度泛函理论(DFT)计算,特别是基于周期性模型的方式是一种可以准确快捷归属其化学位移的方案.然而,由于PCA结构中活泼质子的占位无序,其结构并不能直接或经简单处理后递交计算.本文中,我们通过晶体学手段构建了一个虚拟晶体结构.基于该虚拟结构的^13C化学位移计算值可与实验值准确吻合.此外,不同互变异构状态的PCA表现出不同的特征化学位移,这一信息可被用来分析PCA在其晶体复合物中的分子状态. 展开更多
关键词 分子互变异构 固体核磁共振 DFT计算 两性离子 单晶X射线衍射
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Physical Problems of Quantum Calculation: A Novel Approach 被引量:1
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作者 Vladimir Kirillovich Voronov 《Journal of Physical Science and Application》 2012年第4期115-122,共8页
The manuscript deals with the possibility of application of collective behavior of quantum particles to realize the quantum calculation procedure. The above collective behavior is likely resulted from interelectron co... The manuscript deals with the possibility of application of collective behavior of quantum particles to realize the quantum calculation procedure. The above collective behavior is likely resulted from interelectron correlations, characteristic for strongly correlated systems containing atoms with unoccupied 3d-, 4f- and 5f- shells. Among such systems can be the heterospin systems, complexes of paramagnetic ions of transition metals with organic radicals, because for such objects, spin-spin interaction between unpaired electron spins of different paramagnetic centers is typical. To apply the aforementioned possibility for the organization of real quantum calculations, it is necessary to synthesize such paramagnetic molecules (paramagnetic clusters), where the entangled states will be realized naturally by self-organization of atoms incorporated in these molecules, i.e., without additional external effect of q-bits on the system. The specified self-organization may be due to intramolecular processes and, in particular, intramolecular rearrangement called valence tautomerism, which leads to heterogeneous magnetic states, i.e., to phase layering in paramagnetic cluster owing to interelectron correlations. The states realized during the phase layering can be used for coding the digits. Since such states correspond to specific structures of para-magnetic molecule, they can exist as much as long under certain conditions. In turn, it means that the account of the interelectron correlations, which take place in strongly correlated compounds, allows (at least, in principle) one to create elementary quantum bit of the information capable of modeling the elementary logical operations. Creation of a network of such quantum bits combined in a certain sequence should be considered as a practical step on a way to experimental realization of the idea of quantum computer creation. The group consisting of three quantum points can make the basis of quantum computer. In such a gate, quantum points can be connected via the interaction modeled by spin-spin interaction, characteristic for ABX system in NMR spectroscopy. The tunnel effect, which can be easily realized and controlled, can act as an indicator of bonding in such a block. The calculation procedure can be organized assuming that the initial state of the group corresponds to 1. Infringement of such a state indicates to zero (or, on the contrary). Thus, the calculation in the binary system becomes organized. The creation of a network on the basis of combination of such processors in certain sequence should be considered as a practical step on a way to experimental realization of the idea of the quantum computer creation. 展开更多
关键词 Quantum computer strongly correlated systems self-organization.
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Explanation of Tautomerism and Isomerization in Terms of the Magnetic Field
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作者 Aibassov Yerkin Yemelyanova Valentina +4 位作者 Tussupbayev Nessipbay Shakieva Tatyana Yerzhanova Zhadyra Bulenbayev Maxat Blagikh Evgeniy 《Journal of Chemistry and Chemical Engineering》 2016年第2期96-98,共3页
A study of the influence of magnetic field on the tautomerism, the authors proposed a new method for predicting possible new intra- and intermolecular rearrangements due to tautomerism. The authors have proposed a gen... A study of the influence of magnetic field on the tautomerism, the authors proposed a new method for predicting possible new intra- and intermolecular rearrangements due to tautomerism. The authors have proposed a general mechanism of possible rearrangements and tautomerism. 展开更多
关键词 TAUTOMERISM ISOMERISM benzidine rearrangement magnetic field.
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