Institute of Theoretical and Computational Chemistry, Key Laboratory of Mesoscopic Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, China.
Phys Chem Chem Phys. 2019 Jan 21;21(3):1408-1416. doi: 10.1039/c8cp07084a. Epub 2019 Jan 2.
The O(P) + CH reaction is the first step in acetylene oxidation. The accurate kinetic data and the understanding of the reaction dynamics is of great importance. To this end, a full-dimensional global potential energy surface (PES) for the ground triplet state of the O(P) + CH reaction is constructed based on approximately 85 000 ab initio points calculated at the level of explicitly correlated unrestricted coupled cluster single, double, and perturbative triple excitations with the explicitly correlated polarized valence triple zeta basis set (UCCSD(T)-F12b/VTZ-F12). The PES is fit using the permutation invariant polynomial-neural network (PIP-NN) approach with a total root mean square error of 0.21 kcal mol. The key topographic features of the PES, including multiple potential wells and saddle points along different reaction pathways, are well represented by this fit PES. The kinetics and dynamics of the O(P) + CH reaction are investigated using the quasi-classical trajectory (QCT) method. The calculated rate coefficients are in good agreement with experimental data over a wide temperature range, especially when the temperature is lower than 1500 K. The product branch ratio has also been determined, which indicates the H + HCCO channel as the dominant reaction pathway at 298-3000 K, accounting for 80-90% of the overall rate coefficient, in agreement with experimental observations. The dynamics of the reaction is analyzed in detail.
O(P) + CH 反应是乙炔氧化的第一步。准确的动力学数据和对反应动力学的理解非常重要。为此，我们基于在明确相关的无限制耦合簇单、双和微扰三激发水平上计算的约 85000 个 ab initio 点，使用明确相关极化价三 zeta 基组（UCCSD(T)-F12b/VTZ-F12）构建了 O(P) + CH 反应基态三重态的全维全局势能面（PES）。使用置换不变多项式神经网络（PIP-NN）方法对 PES 进行拟合，总均方根误差为 0.21 kcal/mol。该拟合 PES 很好地代表了 PES 的关键地形特征，包括不同反应途径上的多个势能阱和鞍点。我们使用准经典轨迹（QCT）方法研究了 O(P) + CH 反应的动力学和动力学。计算的速率系数在很宽的温度范围内与实验数据非常吻合，特别是在温度低于 1500 K 时。还确定了产物分支比，表明在 298-3000 K 温度下，H + HCCO 通道是主要的反应途径，占总速率系数的 80-90%，与实验观察结果一致。详细分析了反应动力学。
