Hankel Marlies, Smith Sean C, Meijer Anthony J H M
Centre for Computational Molecular Science, Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, QLD 4072, Australia.
J Chem Phys. 2007 Aug 14;127(6):064316. doi: 10.1063/1.2762220.
We report state-to-state and total reaction probabilities for J=0 and total reaction probabilities for J=2 and 4 for the title reaction, both for ground-state and initially rovibrationally excited reactants. The results for three different potential energy surfaces are compared and contrasted. The potential energy surfaces employed are the DMBE IV surface by Pastrana et al. [J. Phys. Chem. 94, 8073 (1990)], the surface by Troe and Ushakov (TU) [J. Chem. Phys. 115, 3621 (2001)], and the new XXZLG ab initio surface by Xu et al. [J. Chem. Phys. 122, 244305 (2005)]. Our results show that the total reaction probabilities from both the TU and XXZLG surfaces are much smaller in magnitude for collision energies above 1.2 eV compared to the DMBE IV surface. The three surfaces also show different behavior with regards to the effect of initial state excitation. The reactivity is increased on the XXZLG and the TU surfaces and decreased on the DMBE IV surface. Vibrational and rotational product state distributions for the XXZLG and the DMBE IV surface show different behaviors for both types of distributions. Our results show that for energies above 1.25 eV the dynamics on the DMBE IV surface are not statistical. However, there is also evidence that the dynamics on the XXZLG surface are not purely statistical for energies above the onset of the first excited product vibrational state v'=1. The magnitude of the total reaction probability is decreased for J>0 for the DMBE IV and the XXZLG surfaces for ground-state reactants. However, for initially rovibrationally excited reactants, the total reaction probability does not decrease as expected for both surfaces. As a result the total cross section averaged over all Boltzmann accessible rotational states may well be larger than the cross section reported in the literature for j=1.
我们报告了基态和初始振转激发反应物的标题反应中J = 0时的态态反应概率以及J = 2和4时的总反应概率。比较并对比了三种不同势能面的结果。所采用的势能面有Pastrana等人的DMBE IV面[《化学物理杂志》94, 8073 (1990)]、Troe和Ushakov (TU)的面[《化学物理杂志》115, 3621 (2001)]以及Xu等人新的XXZLG从头算面[《化学物理杂志》122, 244305 (2005)]。我们的结果表明，与DMBE IV面相比，对于碰撞能量高于1.2 eV的情况，来自TU面和XXZLG面的总反应概率在数值上要小得多。这三个面在初始态激发的影响方面也表现出不同的行为。XXZLG面和TU面上的反应活性增加，而DMBE IV面上的反应活性降低。XXZLG面和DMBE IV面的振动和转动产物态分布在两种分布类型上都表现出不同的行为。我们的结果表明，对于能量高于1.25 eV的情况，DMBE IV面上的动力学不是统计性的。然而，也有证据表明，对于能量高于第一激发产物振动态v' = 1的起始能量时，XXZLG面上的动力学也不是纯粹统计性的。对于基态反应物，DMBE IV面和XXZLG面的J>0时总反应概率的数值减小。然而，对于初始振转激发的反应物，两个面的总反应概率都没有如预期那样减小。因此，在所有玻尔兹曼可及转动态上平均得到的总截面很可能大于文献中报道的j = 1时的截面。
