Theoretical study of the F(2P) + NH3 → HF + NH2 reaction on an accurate potential energy surface: dynamics and kinetics
Theoretical study of the F(2P) + NH3 → HF + NH2 reaction on an accurate potential energy surface: dynamics and kinetics
复制标题
精确势能面上 F(2P) NH3 -> HF NH2 反应的理论研究：动力学和动力学
DOI：
10.1039/c9cp02113b
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发表时间：
2019
影响因子：
3.3
通讯作者：
Yang Minghui
中科院分区：
文献类型：
--
作者：
Tian Li;Zhu Yongfa;Song Hongwei;Yang Minghui
使用准经典轨迹法在新开发的基电子态势能面 (PES) 上研究了 F 原子与 NH3 的高放热夺氢反应。全维 PES 是通过在 UCCSD(T)-F12/aug-cc-pVTZ 水平上拟合 41 282 ab initio 能量点构建的。拟合中采用灵活的基本不变神经网络方法，总均方根误差为0.13 kcal mol−1。一方面，计算出的微分截面与实验结果相当吻合，表明反应以直接提取和剥离机制为主，而相当多的反应是通过间接“yo-yo”机制发生的。乘积能量划分也很好地再现了实验结果，这可以根据沿最小能量路径的几何变化来理解。另一方面，得到的产物HF的振动状态分布遵循PνHF=2 ≈ PνHF=1 > PνHF=0 > PνHF=3，与分散的实验结果不太一致。此外，计算出的热速率系数在统计误差范围内实际上不具有温度依赖性。
The highly exothermic hydrogen abstraction reaction of the F atom with NH3 is investigated using the quasi-classical trajectory method on a newly developed potential energy surface (PES) for the ground electronic state. The full-dimensional PES is constructed by fitting 41 282 ab initio energy points at the level of UCCSD(T)-F12/aug-cc-pVTZ. The flexible fundamental invariant-neural network method is applied in the fitting, resulting in a total root mean square error of 0.13 kcal mol−1. On one hand, the calculated differential cross sections agree reasonably well with the experimental results and indicate that the reaction is dominated by the direct abstraction and stripping mechanisms while a considerable amount of reaction takes place by the indirect “yo–yo” mechanism. The product energy partition also reproduces well the experimental result, which can be understood according to the geometry change along the minimum energy path. On the other hand, the obtained vibrational state distribution of the product HF follows PνHF=2 ≈ PνHF=1 > PνHF=0 > PνHF=3, less consistent with the scattered experimental results. In addition, the calculated thermal rate coefficients have practically no temperature dependence within the statistical errors.