Describing Chemical Reactivity with Frontier Molecular Orbitalets.
Describing Chemical Reactivity with Frontier Molecular Orbitalets.
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DOI：
10.1021/jacsau.2c00085
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发表时间：
2022-06-27
期刊：
影响因子：
8
通讯作者：
Yang, Weitao
中科院分区：
文献类型：
--
作者：
Yu, Jincheng;Su, Neil Qiang;Yang, Weitao
在分析化学、生物学和材料科学中的各种现象和过程时，物理空间中的局部性对于理解化学反应性至关重要，例如反应官能团和活性位点的概念。前沿分子轨道（FMOs）精确定位了化学键的位置，这些化学键由于相关的轨道能量而具有化学反应性，因此在描述化学反应性方面取得了巨大的成功，主要用于小型系统。然而，对于大型体系，典型分子轨道的离域性质使得FMOs难以突出化学反应性的局域性。为了获得反映化学过程前沿性质的局部分子轨道，我们提出了描述大系统反应性的前沿分子轨道（FMOLs）的概念。轨道小波的概念是近年来在局部轨道尺度校正方法中发展起来的，其目的是消除普通密度泛函近似中的离域误差。小轨道在物理空间和能量空间都是局域化的，因此包含轨道局域化和能量信息。因此，在已占据的轨道中，FMOLs的能量最高，而在未占据的轨道中能量最低。FMOLs在十六进制-1,3,5,7,9,11,13,15-辛烯的平衡几何，分子间和分子内电荷转移体系以及分岔反应的两个过渡态中的应用表明，FMOLs可以通过定位大型化学体系的反应区域来连接化学体系和化学反应的量子力学处理。因此，FMOLs扩展了fmo在小型系统中的作用，并通过能量和局域洞察力描述了大型系统的化学反应性，具有潜在的广泛应用。
Locality in physical space is critical in understanding chemical reactivity in the analysis of various phenomena and processes in chemistry, biology, and materials science, as exemplified in the concepts of reactive functional groups and active sites. Frontier molecular orbitals (FMOs) pinpoint the locality of chemical bonds that are chemically reactive because of the associated orbital energies and thus have achieved great success in describing chemical reactivity, mainly for small systems. For large systems, however, the delocalization nature of canonical molecular orbitals makes it difficult for FMOs to highlight the locality of the chemical reactivity. To obtain localized molecular orbitals that also reflect the frontier nature of the chemical processes, we develop the concept of frontier molecular orbitalets (FMOLs) for describing the reactivity of large systems. The concept of orbitalets was developed recently in the localized orbital scaling correction method, which aims for eliminating the delocalization error in common density functional approximations. Orbitalets are localized in both physical and energy spaces and thus contain both orbital locality and energy information. The FMOLs are thus the orbitalets with energies highest among occupied orbitalets and lowest among unoccupied ones. The applications of FMOLs to hexadeca-1,3,5,7,9,11,13,15-octaene in its equilibrium geometry, inter- and intra-molecular charge-transfer systems, and two transition states of a bifurcating reaction demonstrate that FMOLs can connect quantum mechanical treatments of chemical systems and chemical reactivities by locating the reactive region of large chemical systems. Therefore, FMOLs extend the role of FMOs for small systems and describe the chemical reactivity of large systems with energy and locality insight, with potentially broad applications.