Shen Zhitao, Cao Jianwei, Bian Wensheng
Beijing National Laboratory for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China.
J Chem Phys. 2015 Apr 28;142(16):164309. doi: 10.1063/1.4919406.
Accurate quantum dynamics calculations for the C((1)D) + H2 reaction are performed using a real wave packet approach with full Coriolis coupling. The newly constructed ZMB-a ab initio potential energy surface [Zhang et al., J. Chem. Phys. 140, 234301 (2014)] is used. The integral cross sections (ICSs), differential cross sections (DCSs), and product state distributions are obtained over a wide range of collision energies. In contrast to previous accurate quantum dynamics calculations on the reproducing kernel Hilbert space potential energy surface, the present total ICS is much larger at low collision energies, yielding larger rate coefficients in better agreement with experiment and with slight inverse temperature dependence. Meanwhile, interesting nonstatistical behaviors in the DCSs are revealed. In particular, the DCSs display strong oscillations with the collision energy; forward biased product angular distribution appears when only small J partial wave contributions are included; alternate forward and backward biases emerge with very small increments of collision energy; and the rotational state-resolved DCSs show strong oscillations with the scattering angle. Nevertheless, the total DCSs can be roughly regarded as backward-forward symmetric over the whole energy range and are in reasonably good agreement with the available experimental measurements.
采用包含完全科里奥利耦合的实波包方法，对C((1)D) + H2反应进行了精确的量子动力学计算。使用了新构建的ZMB-a从头算势能面[Zhang等人，《化学物理杂志》140, 234301 (2014)]。在广泛的碰撞能量范围内获得了积分截面(ICSs)、微分截面(DCSs)和产物态分布。与之前在再生核希尔伯特空间势能面上进行的精确量子动力学计算不同，当前的总ICS在低碰撞能量下要大得多，产生的速率系数更大，与实验结果更吻合，且具有轻微的逆温度依赖性。同时，在DCSs中揭示了有趣的非统计行为。特别是，DCSs随碰撞能量呈现强烈振荡；当仅包含小J分波贡献时，出现前向偏置的产物角分布；随着碰撞能量的非常小的增量，交替出现前向和后向偏置；并且转动态分辨的DCSs随散射角呈现强烈振荡。然而，总DCSs在整个能量范围内大致可视为前后对称，并且与现有的实验测量结果相当吻合。
