Journal Articles Nature Communications Year : 2018

The reaction of hydroxyl and methylperoxy radicals is not a major source of atmospheric methanol

M. Anwar H. Khan
  • Function : Author
Dudley Shallcross
  • Function : Author

Abstract

Methanol is a benchmark for understanding tropospheric oxidation, but is underpredicted by up to 100% in atmospheric models. Recent work has suggested this discrepancy can be reconciled by the rapid reaction of hydroxyl and methylperoxy radicals with a methanol branching fraction of 30%. However, for fractions below 15%, methanol underprediction is exacerbated. Theoretical investigations of this reaction are challenging because of intersystem crossing between singlet and triplet surfaces – ∼45% of reaction products are obtained via intersystem crossing of a pre-product complex – which demands experimental determinations of product branching. Here we report direct measurements of methanol from this reaction. A branching fraction below 15% is established, consequently highlighting a large gap in the understanding of global methanol sources. These results support the recent high-level theoretical work and substantially reduce its uncertainties.

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hal-02322065 , version 1 (25-02-2025)

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Rebecca Caravan, M. Anwar H. Khan, Judit Zádor, Leonid Sheps, Ivan Antonov, et al.. The reaction of hydroxyl and methylperoxy radicals is not a major source of atmospheric methanol. Nature Communications, 2018, 9 (1), ⟨10.1038/s41467-018-06716-x⟩. ⟨hal-02322065⟩
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