Electron Density Geometry and the Quantum Theory of Atoms in Molecules
Electron Density Geometry and the Quantum Theory of Atoms in Molecules
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电子密度几何和分子中原子的量子理论
DOI：
10.1021/acs.jpca.1c09359
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发表时间：
2021
期刊：
影响因子：
--
通讯作者：
Eberhart, M. E.
中科院分区：
文献类型：
--
作者：
Wilson, Timothy R.;Alexandrova, Anastassia N.;Eberhart, M. E.
提出了一种新的电荷密度分析方法--等值面曲率再分布法，并将其应用于甲醛中羰基氧活化的玩具问题。电子电荷密度的等值面表示使我们能够将严格的几何约束的封闭表面对扰动的电荷密度响应的分析和化学解释。视觉检查所施加的外部电场产生的二维等值面运动揭示了等值面曲率如何在原子内部和原子之间流动，并且分子可以唯一地完全划分为具有正曲率和负曲率的化学显著区域。这些概念表明，羰基氧活化主要是通过曲率和电荷重新分配内，而不是之间的巴德原子。用梯度束分析法--将甲醛分解为以QTAIM零通量面为界的无穷小体积元--验证了视觉等值面检验的观测结果。甲醛羰基分析的结果，然后被证明是可转移到底物羰基的甾酮异构酶，奠定了基础，将这种方法扩展到酶催化的问题。
A novel form of charge density analysis, that of isosurface curvature redistribution, is formulated and applied to the toy problem of carbonyl oxygen activation in formaldehyde. The isosurface representation of the electron charge density allows us to incorporate the rigorous geometric constraints of closed surfaces toward the analysis and chemical interpretation of the charge density response to perturbations. Visual inspection of 2D isosurface motion resulting from applied external electric fields reveals how the isosurface curvature flows within and between atoms and that a molecule can be uniquely and completely partitioned into chemically significant regions of positive and negative curvatures. These concepts reveal that carbonyl oxygen activation proceeds primarily through curvature and charge redistribution within rather than between Bader atoms. Using gradient bundle analysis─the partitioning of formaldehyde into infinitesimal volume elements bounded by QTAIM zero-flux surfaces─the observations from visual isosurface inspection are verified. The results of the formaldehyde carbonyl analysis are then shown to be transferable to the substrate carbonyl in the ketosteroid isomerase enzyme, laying the groundwork for extending this approach to the problems of enzymatic catalysis.