Channel-specific angular distributions of HCl and CH3 products from the reaction of atomic chlorine with stretch-excited methane
Channel-specific angular distributions of HCl and CH3 products from the reaction of atomic chlorine with stretch-excited methane
复制标题
氯原子与拉伸激发甲烷反应产生的 HCl 和 CH3 产物的通道特定角分布
DOI：
10.1063/1.1493192
复制
发表时间：
2002
影响因子：
4.4
通讯作者：
R. Zare
中科院分区：
文献类型：
--
作者：
Z. Kim;H. Bechtel;R. Zare
含有甲烷和分子氯的光束膨胀到真空中，其中甲烷被两个量子的 C-H 拉伸（四个 C-H 键中的两个各一个量子）激发。该反应由 Cl2 在 355 nm 处光解产生的快速 Cl 原子引发，并使用共振增强多光子电离以特定状态的方式检测所得的 CH3 和 HCl 产物。 HCl 和 CH3 产品的速度相关空间各向异性 (βprod) 允许识别三个主要产品通道。它们按重要性顺序排列： (a) HCl (v=0)+CH3 [ν1（对称拉伸）或 ν3（不对称 拉伸）=1]； (b) HCl (v=1)+CH3 [ν2(伞 弯)=1)]； (c) HCl (v=1)+CH3 (ν1=1)。无法检测到 CH3 (v=0) 产物，HCl (v=2) 产物很少。通道（a）和（c）以振动绝热方式进行，而通道（b）似乎涉及非绝热相互作用，涉及甲烷中的低频弯曲模式，与甲基自由基中的弯曲模式相关......
A beam containing methane and molecular chlorine is expanded into a vacuum where the methane is excited with two quanta of C–H stretching (one quantum each in two of the four C–H bonds). The reaction is initiated by fast Cl atoms generated by photolysis of Cl2 at 355 nm, and the resulting CH3 and HCl products are detected in a state-specific manner using resonance-enhanced multiphoton ionization. Speed-dependent spatial anisotropies (βprod) of HCl and CH3 products allow identification of three major product channels. They are in order of importance: (a) HCl (v=0)+CH3 [ν1 (symmetric stretch) or ν3 (asymmetric stretch)=1]; (b) HCl (v=1)+CH3 [ν2(umbrella bend)=1)]; and (c) HCl (v=1)+CH3 (ν1=1). The CH3 (v=0) product cannot be detected, and the HCl (v=2) product is minor. Channels (a) and (c) proceed in a vibrationally adiabatic manner, whereas channel (b) appears to involve the nonadiabatic interaction involving the low frequency bending mode in methane that correlates to the bending mode in the methyl radic...