Mroz Austin M, Davenport Audrey M, Sterling Jasper, Davis Joshua, Hendon Christopher H
Department of Chemistry and Biochemistry, University of Oregon Eugene OR 97403 USA
Chem Sci. 2022 May 11;13(22):6558-6566. doi: 10.1039/d2sc00780k. eCollection 2022 Jun 7.
Chemical shape and size play a critical role in chemistry. The van der Waals (vdW) radius, a familiar manifold used to quantify size by assuming overlapping spheres, provides rapid estimates of size in atoms, molecules, and materials. However, the vdW method may be too rigid to describe highly polarized systems and chemical species that stray from spherical atomistic environments. To deal with these exotic chemistries, numerous alternate methods based on electron density have been presented. While each boasts inherent generality, all define the size of a chemical system, in one way or another, by its electron density. Herein, we revisit the longstanding problem of assessing sizes of atoms and molecules, instead through examination of the local electric field produced by them. While conceptually different than nuclei-centered methods like that of van der Waals, the field assesses . This approach implicitly accounts for long-range fields in highly polar systems and predicts that cations should affect more space than neutral counterparts.
化学形状和大小在化学中起着关键作用。范德华（vdW）半径是一种通过假设重叠球体来量化大小的常见方法，可快速估算原子、分子和材料的大小。然而，范德华方法可能过于僵化，无法描述高度极化的系统以及偏离球形原子环境的化学物种。为了处理这些奇特的化学情况，人们提出了许多基于电子密度的替代方法。虽然每种方法都有其固有的通用性，但所有方法都以某种方式通过电子密度来定义化学系统的大小。在此，我们重新审视评估原子和分子大小这一长期存在的问题，而是通过研究它们产生的局部电场来进行。虽然从概念上讲，这与像范德华那样以原子核为中心的方法不同，但电场评估……这种方法隐含地考虑了高度极化系统中的长程场，并预测阳离子比中性对应物应影响更大的空间。
