Research Center of Heterogeneous Catalysis and Engineering Sciences, School of Chemical Engineering and Energy, Zhengzhou University, Zhengzhou 450001, China.
State Key Laboratory of Molecular Reaction Dynamics and Center for Theoretical Computational Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, People's Republic of China.
J Chem Phys. 2017 Jul 14;147(2):024702. doi: 10.1063/1.4991562.
As one benchmark system of CH dissociation on the Ni(111) surface, it is of great significance to explore the role of each degree of freedom (DOF) of reactant CH in its first C-H bond dissociation from quantum dynamics simulations. Here, the influence of the CH stretching DOF of methyl limited in C symmetry is quantitatively investigated as well as the important role of azimuth. We calculated the sticking probabilities, S, of ground state (GS) CH dissociation on a rigid Ni(111) surface by performing some seven-dimensional to nine-dimensional (9D) quantum dynamics simulations based on one highly accurate and fifteen-dimensional (15D) ab initio potential energy surface which we recently developed. Our direct quantum dynamics results show that S of GS CH on four given surface impact sites are weakly enhanced by adding the CH stretching DOF of methyl but strongly weakened by the DOF of azimuth. Furthermore, using a 9D quantum dynamics model, we improve the post-treatment model for treating the influence of surface impact sites through a linear relationship between the effective potential barriers and the distances relative to that on the transition state site. These developed high-dimensional quantum dynamics models and improved post-treatments can be usefully extended for studying some complex polyatomic gas-surface reactions by other theoretical groups.
作为 Ni(111) 表面 CH 离解的基准体系之一，从量子动力学模拟中探索反应物 CH 的每个自由度 (DOF) 在其第一个 C-H 键离解中的作用具有重要意义。在这里，我们定量研究了 C 对称限制的甲基 CH 伸缩自由度以及方位的重要作用。我们通过执行一些基于我们最近开发的高精度十五维 (15D) 从头算势能面的七维到九维 (9D) 量子动力学模拟，计算了基态 (GS) CH 在刚性 Ni(111) 表面上的离解 sticking 概率 S。我们的直接量子动力学结果表明，在四个给定的表面冲击位点上，GS CH 的 S 通过添加甲基的 CH 伸缩自由度而被弱增强，但通过方位自由度而被强烈削弱。此外，我们使用 9D 量子动力学模型，通过有效势垒与相对于过渡态位点的距离之间的线性关系，改进了用于处理表面冲击位点影响的后处理模型。这些开发的高维量子动力学模型和改进的后处理可以被其他理论小组有效地扩展用于研究一些复杂的多原子气体-表面反应。
