Falcinelli Stefano, Vecchiocattivi Franco, Farrar James M, Pirani Fernando
Department of Civil and Environmental Engineering, University of Perugia, Via G. Duranti 93, 06125 Perugia, Italy.
Department of Chemistry, University of Rochester, 14627 Rochester, New York, United States.
J Phys Chem A. 2021 Apr 29;125(16):3307-3315. doi: 10.1021/acs.jpca.1c00688. Epub 2021 Apr 15.
A new theoretical method, developed by our laboratory to describe the microscopic dynamics of gas-phase elementary chemi-ionization reactions, has been applied recently to study prototype atom-atom processes involving reactions between electronically excited metastable Ne*(P) and heavier noble gas atoms. Important aspects of electronic rearrangement selectivity have been emphasized that suggested the existence of two fundamental microscopic reaction mechanisms. The distinct mechanisms, which are controlled by intermolecular forces of chemical and noncovalent nature respectively, emerge under different conditions, and their balance depends on the collision energy regime investigated. The present paper provides the first step for the extension of the method to cases involving molecules of increasing complexity, whose chemi-ionization reactions are of relevance in several fields of basic and applied researches. The focus is here on the reactions of Ne* with simple inorganic molecules as Cl and NH, and the application of the method discloses relevant features of the reaction microscopic evolution. In particular, this study shows that the balance of two fundamental reaction mechanisms depends not only on the collision energy and on the relative orientation of reagents but also on the orbital angular momentum of each collision complex. The additional insights so emphasized are of general relevance to assess in detail the stereodynamics of many other elementary processes.
我们实验室开发的一种描述气相基元化学电离反应微观动力学的新理论方法，最近已应用于研究涉及电子激发亚稳态Ne*(P)与较重惰性气体原子之间反应的原型原子 - 原子过程。已经强调了电子重排选择性的重要方面，这表明存在两种基本的微观反应机制。这两种不同的机制分别由化学和非共价性质的分子间力控制，在不同条件下出现，它们的平衡取决于所研究的碰撞能量范围。本文为将该方法扩展到涉及越来越复杂分子的情况迈出了第一步，这些分子的化学电离反应在基础研究和应用研究的多个领域都具有相关性。这里的重点是Ne*与简单无机分子如Cl和NH的反应，该方法的应用揭示了反应微观演化的相关特征。特别是，这项研究表明，两种基本反应机制的平衡不仅取决于碰撞能量和反应物的相对取向，还取决于每个碰撞复合物的轨道角动量。如此强调的这些额外见解对于详细评估许多其他基元过程的立体动力学具有普遍意义。
