Over the past ten years or so, great advances in our understanding of the dynamics of elementary (bimolecular) polyatomic reactions in the gas-phase have occurred. This has been made possible by critical improvements (a) in crossed molecular beam (CMB) instruments with rotating mass spectrometric detection and time-of-flight analysis, especially following the implementation of soft ionization (by tunable low energy electrons or vacuum-ultraviolet synchrotron radiation) for product detection with increased sensitivity and universal detection power, and (b) in REMPI-slice velocity map ion imaging (VMI) detection techniques in pulsed CMB experiments for obtaining product pair-correlated information through high-resolution measurements directly in the center of mass system. The improved universal CMB method is permitting us to identify all primary reaction products, characterize their formation dynamics, and determine the branching ratios (BRs) for multichannel non-adiabatic reactions, such as those of ground state oxygen atoms, O(³P), with unsaturated hydrocarbons (alkynes, alkenes, dienes). The improved slice VMI CMB technique is permitting us to explore at an unprecedented level of detail, through pair-correlated measurements, the reaction dynamics of a prototype polyatomic molecule such as CH₄ (and isotopologues) in its ground state with a variety of important X radicals such as F, Cl, O, and OH. In this review, we highlight this recent progress in the field of CMB reaction dynamics, with an emphasis on the experimental side, but with the related theoretical work, at the level of state-of-the-art calculations of both the underlying potential energy surfaces and the reaction dynamics, noted throughout. In particular, the focus is (a) on the effect of molecular complexity and structure on product distributions, branching ratios and role of intersystem crossing for the multichannel, addition–elimination reactions of unsaturated hydrocarbons with O atoms, and (b) on the very detailed dynamics of the abstraction reactions of ground-state methane (and isotopologues) with atoms (F, Cl, O) and diatoms (OH), with inclusion of also rotational mode specificity in the vibrationally excited methane reactions.

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横梁多原子反应动力学：最新进展和新见解

在过去的十年左右的时间里，我们对气相中基本（双分子）多原子反应动力学的理解有了长足的进步。通过对具有旋转质谱检测和飞行时间分析的交叉分子束（CMB）仪器进行重大改进（a），尤其是在实现软电离后（通过可调低能电子或真空紫外同步加速器），可以实现这一目标辐射）用于提高灵敏度和通用检测能力的产品检测，以及（b）在脉冲CMB实验中的REMPI切片速度图离子成像（VMI）检测技术中，可通过中心直接通过高分辨率测量获得产品对相关信息质量体系。³ P），带有不饱和烃（炔烃，烯烃，二烯）。改进的切片VMI CMB技术使我们能够通过成对相关的测量以前所未有的细节水平探索原型多原子分子（例如CH _4）的反应动力学（和同位素）处于基态，并带有各种重要的X自由基，例如F，Cl，O和OH。在这篇综述中，我们重点介绍了CMB反应动力学领域的最新进展，重点是实验方面，但在相关理论工作的基础上，对两个潜在势能进行了最新的计算。表面和反应动力学，贯穿全文。特别是，重点是（a）分子复杂性和结构对产物分布，支链比率和多通道系统间交叉的作用，不饱和烃与O原子的加-消除反应的影响，以及（b）对基态甲烷（和同位素）与原子（F，Cl，O）和硅藻（OH）的抽象反应的详细动力学，