Study on the kinetics and dynamics of the H2 + NH2- reaction on a high-level ab initio potential energy surface.
Study on the kinetics and dynamics of the H2 + NH2- reaction on a high-level ab initio potential energy surface.
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DOI：
10.1039/d1cp02423j
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发表时间：
2021-09
期刊：
影响因子：
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通讯作者：
Mengyi Pan;Haipan Xiang;Yong Li;H. Song
中科院分区：
文献类型：
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作者：
Mengyi Pan;Haipan Xiang;Yong Li;H. Song
气相离子-分子反应在化学和物理的许多领域都起着重要的作用。氨基阴离子与氢分子的反应是涉及阴离子的最简单的质子转移反应之一。用基本不变量-神经网络方法建立了NH_2~-+H_2反应的全维势能面，均方根误差为0.116千卡·摩尔~(-1)。然后对新开发的PES进行了准经典轨道计算，得到了积分截面、微分截面和热速率系数。该反应有质子转移和氢交换两个反应通道。在所研究的能量范围内，质子转移通道的反应性比氢交换通道的反应性大一个或两个数量级。H2的振动激发促进了质子转移反应，而NH2-的每个振动模式的基态激发对质子转移反应的影响可以忽略不计。此外，在150~750K温度范围内，质子转移反应的理论速率系数与已有的实验结果成反比。
Gas-phase ion-molecule reactions play major roles in many fields of chemistry and physics. The reaction of an amino radical anion with a hydrogen molecule is one of the simplest proton transfer reactions involving anions. A globally accurate full-dimensional potential energy surface (PES) for the NH2- + H2 reaction is developed by the fundamental invariant-neural network method, resulting in a root mean square error of 0.116 kcal mol-1. Quasi-classical trajectory calculations are then carried out on the newly developed PES to give integral cross sections, differential cross sections and thermal rate coefficients. This reaction has two reaction channels, proton transfer and hydrogen exchange. The reactivity of the proton transfer channel is about one or two orders of magnitude stronger than that of the hydrogen exchange channel in the energy range studied. Vibrational excitation of H2 promotes the proton transfer reaction, while fundamental excitation of each vibrational mode of NH2- has a negligible effect. In addition, the theoretical rate coefficients of the proton transfer reaction on the PES show inverse temperature dependence from 150 to 750 K, in accordance with the available experimental results.