物理化学学报 >> 2018, Vol. 34 >> Issue (5): 503-513.doi: 10.3866/PKU.WHXB201709252

所属专题: 密度泛函理论中的化学概念特刊

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通过价层电子密度分析展现分子电子结构

卢天*(),陈沁雪   

  • 收稿日期:2017-08-31 发布日期:2018-01-24
  • 通讯作者: 卢天 E-mail:sobereva@sina.com

Revealing Molecular Electronic Structure via Analysis of Valence Electron Density

Tian LU*(),Qinxue CHEN   

  • Received:2017-08-31 Published:2018-01-24
  • Contact: Tian LU E-mail:sobereva@sina.com

摘要:

迄今已有众多实空间函数被提出用来揭示化学上感兴趣的分子电子结构特征,例如化学键、孤对电子和多中心电子共轭。在这些分析方法中,电子定域化函数(ELF)、电子密度的拉普拉斯(∇2ρ)和变形密度(ρdef)被广泛用于实际研究。众所周知,分析分子的总电子密度无法像以上提及的方法那样展现出与分子电子结构有关的丰富的信息。但是,在本文中,通过数个实例以及通过与ELF、∇2ρρdef的对比,我们指出若只关注价层电子密度分布,分子电子结构特征也是可能被探究的。我们发现对大多数情况,对非常简单的价层电子密度的分析也可以给出与ELF、∇2ρρdef分析类似的信息,并且这种分析具有计算复杂度更低的额外优点。我们希望本文的工作可以使得化学家们关注长期被忽视的价层电子密度所具有的重要价值。也值得注意的是,价层电子密度分析并非完全没有缺点,当这种方法无法提供丰富信息的时候,研究者仍需借助于其它类型的分析手段。

关键词: 电子密度, 波函数分析, 化学键, 电子定域化函数, 分子中的原子, 密度泛函理论, 电子密度的拉普拉斯

Abstract:

Numerous real space functions have been purposed so far for unveiling chemically interesting molecular electronic structure characteristics, such as chemical bonds, lone pairs, and multicenter electronic conjugations. Among these analysis methods, electron localization function (ELF), Laplacian of electron density (∇2ρ), and deformation density (ρdef) were widely employed in practical research work. It is well known that the analysis of total molecular electron density is not sufficient for revealing much information about the molecular electronic structure like the above-mentioned methods. However, in this work, using several instances and by comparing with the ELF, ∇2ρ, and ρdef values, we show that it is possible to explore molecular electronic structure characteristics if one solely focuses on investigating the valence electron density distribution. It is found that for most cases, analysis of the very simple valence electron density conveys analogous information as ELF, ∇2ρ and ρdef analyses, with additional advantage of reduced computational complexity. We hope that this work will bring chemists' attention to the high importance of valence electron density, which has been largely ignored for a long time. It should also be noticed that the valence electron density analysis is not free from drawbacks, and when this method is unable to provide an informative picture, one has to use other analysis methods.

Key words: Electron density, Wavefunction analysis, Chemical bond, Electron localization Function, Atoms in molecules, Density functional theory, Laplacian of electron density, Deformation density

MSC2000: 

  • O641