Bai Chen, Kale Seyit, Herzfeld Judith
Department of Chemistry , Brandeis University , Waltham , MA 02454 , USA . Email:
Chem Sci. 2017 Jun 1;8(6):4203-4210. doi: 10.1039/c7sc01181d. Epub 2017 Apr 19.
For a century now, "Lewis dots" have been a mainstay of chemical thinking, teaching and communication. However, chemists have assumed that this semi-classical picture of electrons needs to be abandoned for quantitative work, and the recourse in computational simulations has been to the extremes of first principles treatments of electrons on the one hand and force fields that avoid explicit electrons on the other hand. Given both the successes and limitations of these highly divergent approaches, it seems worth considering whether the Lewis dot picture might be made quantitative after all. Here we review progress to that end, including variations that have been implemented and examples of applications, specifically the acid-base behavior of water, several organic reactions, and electron dynamics in silicon fracture. In each case, the semi-classical approach is highly efficient and generates reasonable and readily interpreted reaction trajectories in turnkey fashion (, without any input about products). Avenues for further progress are also discussed.
一个世纪以来，“路易斯点式”一直是化学思维、教学和交流的支柱。然而，化学家们认为，对于定量研究，这种电子的半经典图景需要摒弃，在计算模拟中，一方面求助于对电子进行第一性原理处理的极端方法，另一方面则是避免明确考虑电子的力场方法。鉴于这些高度不同的方法既有成功之处也有局限性，似乎值得考虑路易斯点式是否终究可以实现定量。在此，我们综述了为此所取得的进展，包括已实施的变体以及应用实例，特别是水的酸碱行为、几个有机反应以及硅断裂中的电子动力学。在每种情况下，半经典方法都非常高效，并且能以交钥匙方式（无需任何关于产物的输入）生成合理且易于解释的反应轨迹。还讨论了进一步取得进展的途径。
