Mechanism of the Gas-Phase HO + H2O → H2O + OH Reaction and Several Associated Isotope Exchange Reactions: A Canonical Variational Transition State Theory Plus Multidimensional Tunneling Calculation
Mechanism of the Gas-Phase HO + H2O → H2O + OH Reaction and Several Associated Isotope Exchange Reactions: A Canonical Variational Transition State Theory Plus Multidimensional Tunneling Calculation
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DOI：
10.1021/jp983749t
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发表时间：
1999-02
影响因子：
2.9
通讯作者：
Laura Masgrau;A. González-Lafont;J. M. Lluch
中科院分区：
文献类型：
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作者：
Laura Masgrau;A. González-Lafont;J. M. Lluch
氢氧根从分子中提取氢是几个与大气化学关键相关的反应机制中的一个重要步骤。实验确定了最简单的抽氢反应之一HO + HOH→HOH + OH(1)的速率常数在300 K时的上限。这个反应本身就很有趣，因为伴随的同位素交换反应H18O + HOH→H18OH + OH(2)和DO + HOH→DOH + OH(3)可能会影响平流层水的同位素组成。在300 ~ 420 K区间（反应2）和300 K时（反应3），实验测量了这两个反应的速率常数。此外，还给出了反应HO + DOD→HOD + OD(4)的速率常数在300 K时的上限。本文用从头算电子结构理论计算了上述四种氢（氘）转移反应的速率常数及其与温度的关系。
Hydrogen abstraction from a molecule by OH is an important step in several reaction mechanisms of a key relevance in the chemistry of the atmosphere. The upper limit at 300 K for the rate constant of one of the simplest hydrogen abstraction reactions, HO + HOH → HOH + OH (1), has been experimentally established. This reaction is intrinsicaly interesting because the associated isotope exchange reactions, H18O + HOH → H18OH + OH (2) and DO + HOH → DOH + OH (3), could affect the isotopic composition of the stratospheric water. The rate constants for those two reactions have also been experimentally measured in the interval 300−420 K (reaction 2) and at 300 K (reaction 3). In addition, the upper limit at 300 K for the rate constant of the reaction HO + DOD → HOD + OD (4) has also been given. In this paper, we have theoretically calculated the rate constants and their temperature dependence for the above-mentioned four hydrogen (deuterium) transfer reactions by means of ab initio electronic structure calculati...