论文标题
势能表面在化学反应动力学中的深度和平坦度的作用
The role of depth and flatness of a potential energy surface in chemical reaction dynamics
论文作者
论文摘要
在这项研究中，我们分析了势能表面的几何形状的变化在深度和平坦方面如何影响反应动力学。我们在一个和两个自由度（DOF）哈密顿法线形式的背景下制定深度和平坦度，用于鞍形节点分叉，并量化其对化学反应动力学的影响。在最近的一项工作中，García-Garrido，Naik和Wiggins说明了如何改变势能表面（PES）的良好深度会导致鞍形节点分叉。他们已经展示了与等级-1鞍形相关的圆柱形歧管的几何形状在向鞍形节点分叉的途径中变化。使用此处介绍的配方，我们展示了势能的参数如何控制深度和平坦度，并在化学反应的定量测量中展示了它们的作用。我们通过计算瓶颈宽度和良好宽度，反应概率（也称为过渡分数或人口分数），间隙时间（或第一个通过时间）分布以及通过分裂表面（DS）的定向通量（ds）来量化深度和平坦度的这种作用。这些定量度量获得的结果与对反应动力学的定性理解一致。
In this study, we analyze how changes in the geometry of a potential energy surface in terms of depth and flatness can affect the reaction dynamics. We formulate depth and flatness in the context of one and two degree-of-freedom (DOF) Hamiltonian normal form for the saddle-node bifurcation and quantify their influence on chemical reaction dynamics. In a recent work, García-Garrido, Naik, and Wiggins illustrated how changing the well-depth of a potential energy surface (PES) can lead to a saddle-node bifurcation. They have shown how the geometry of cylindrical manifolds associated with the rank-1 saddle changes en route to the saddle-node bifurcation. Using the formulation presented here, we show how changes in the parameters of the potential energy control the depth and flatness and show their role in the quantitative measures of a chemical reaction. We quantify this role of the depth and flatness by calculating the ratio of the bottleneck-width and well-width, reaction probability (also known as transition fraction or population fraction), gap time (or first passage time) distribution, and directional flux through the dividing surface (DS) for small to high values of total energy. The results obtained for these quantitative measures are in agreement with the qualitative understanding of the reaction dynamics.
