Mauguière Frédéric A L, Collins Peter, Kramer Zeb C, Carpenter Barry K, Ezra Gregory S, Farantos Stavros C, Wiggins Stephen
School of Mathematics, University of Bristol, Bristol BS8 1TW, United Kingdom.
Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853, USA.
J Chem Phys. 2016 Feb 7;144(5):054107. doi: 10.1063/1.4940798.
We examine the phase space structures that govern reaction dynamics in the absence of critical points on the potential energy surface. We show that in the vicinity of hyperbolic invariant tori, it is possible to define phase space dividing surfaces that are analogous to the dividing surfaces governing transition from reactants to products near a critical point of the potential energy surface. We investigate the problem of capture of an atom by a diatomic molecule and show that a normally hyperbolic invariant manifold exists at large atom-diatom distances, away from any critical points on the potential. This normally hyperbolic invariant manifold is the anchor for the construction of a dividing surface in phase space, which defines the outer or loose transition state governing capture dynamics. We present an algorithm for sampling an approximate capture dividing surface, and apply our methods to the recombination of the ozone molecule. We treat both 2 and 3 degrees of freedom models with zero total angular momentum. We have located the normally hyperbolic invariant manifold from which the orbiting (outer) transition state is constructed. This forms the basis for our analysis of trajectories for ozone in general, but with particular emphasis on the roaming trajectories.
我们研究了在势能面上不存在临界点的情况下控制反应动力学的相空间结构。我们表明，在双曲不变环面附近，可以定义相空间分隔面，这些分隔面类似于在势能面临界点附近控制从反应物到产物转变的分隔面。我们研究了双原子分子捕获原子的问题，并表明在远离势能上任何临界点的大原子 - 双原子距离处存在一个正常双曲不变流形。这个正常双曲不变流形是在相空间中构建分隔面的锚点，该分隔面定义了控制捕获动力学的外部或宽松过渡态。我们提出了一种用于采样近似捕获分隔面的算法，并将我们的方法应用于臭氧分子的重组。我们处理总角动量为零的二维和三维自由度模型。我们已经找到了构建轨道（外部）过渡态的正常双曲不变流形。这构成了我们一般对臭氧轨迹分析的基础，但特别强调漫游轨迹。
