Lu Zhou, Hu Qichi, Oakman Jonathan E, Continetti Robert E
Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093-0340, USA.
J Chem Phys. 2007 May 21;126(19):194305. doi: 10.1063/1.2731787.
An experimental study of the dissociative photodetachment (DPD) dynamics of HOCO(-) and DOCO(-) at a photon energy of 3.21 eV has been carried out to probe the potential energy surface of the HOCO free radical and the dynamics of the OH+CO-->H+CO(2) reaction. These photoelectron-photofragment coincidence experiments allow the identification of photodetachment processes leading to the production of stable HOCO free radicals and both the H+CO(2) and OH+CO dissociation channels on the neutral surface. Isotopic substitution by deuterium in the parent ion is observed to reduce the product branching ratio for the D+CO(2) channel, consistent with tunneling playing a role in this dissociation pathway. Other isotope effects on the detailed partitioning of kinetic energy between photoelectrons and photofragments are also discussed. The results are compared to recent theoretical predictions of this DPD process, and evidence for the involvement of vibrationally excited HOCO(-) anions is discussed.
在3.21 eV光子能量下，对HOCO(-)和DOCO(-)的离解光剥离（DPD）动力学进行了实验研究，以探测HOCO自由基的势能面以及OH + CO→H + CO₂反应的动力学。这些光电子 - 光碎片符合实验能够识别导致稳定HOCO自由基产生的光剥离过程，以及中性表面上的H + CO₂和OH + CO解离通道。观察到母体离子中用氘进行同位素取代会降低D + CO₂通道的产物分支比，这与隧道效应在该解离途径中起作用一致。还讨论了其他同位素对光电子和光碎片之间动能详细分配的影响。将结果与该DPD过程的最新理论预测进行了比较，并讨论了振动激发的HOCO(-)阴离子参与的证据。
