Comparison of Three Isoelectronic Multiple-Well Reaction Systems: OH + CH2O, OH + CH2CH2, and OH + CH2NH

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• 作者：Mohamad Akbar Ali ; John R. Barker
• 刊名：Journal of Physical Chemistry A
• 出版年：2015
• 出版时间：July 16, 2015
• 年：2015
• 卷：119
• 期：28
• 页码：7578-7592
• 全文大小：771K
• ISSN：1520-5215

文摘

Methylenimine (CH₂NH) has been predicted to be a product of the atmospheric photo-oxidation of methylamine, but its atmospheric reactions have not been measured. In this paper, we report potential energy surfaces (PESs) and rate constants for OH + CH₂NH and its isoelectronic analogues OH + CH₂O and OH + CH₂CH₂, which are more fully understood. The PESs were computed using the BHandHLYP/aug-cc-pVTZ and CCSD(T)/aug-cc-pVTZ levels of theory. Canonical variational transition state theory and Rice鈥揜amsperger鈥揔assel鈥揗arcus and master equation modeling were used to calculate temperature- and pressure-dependent rate constants, with particular emphasis on the OH + reactant entrance channels and the effects of prereactive complexes. The computed results are in reasonable agreement with experimental data where they can be compared and also with the results of previous theoretical calculations. The results show that to some extent OH radicals both add to the carbon center double bond in CH₂NH and abstract methylene hydrogen atoms, as in the OH + CH₂O and OH + CH₂CH₂ reactions, respectively, but the dominant pathway is abstraction of the hydrogen from N鈥揌. The computed rate constants are suitable for both atmospheric and combustion modeling.