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

Rebecca Caravan; Anwar Khan; Judit Zador; Leonid Sheps; Ivan Antonov; Brandon Rotavera; Krupa Ramasesha; Kendrew Au; Ming-Wei Chen; Daniel Rosch; David Osborn; Christa Fittschen; Coralie Schoemaecker; Marius Duncianu; ASma Grira; Sebastien Dusanter; Alexandre Tomas; Carl Percival; Dudley Shallcross; Craig Taatjes

doi:10.1038/s41467-018-06716-x

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

Rebecca Caravan, Anwar Khan, Judit Zador, Leonid Sheps, Ivan Antonov, Brandon Rotavera, Krupa Ramasesha, Kendrew Au, Ming-Wei Chen, Daniel Rosch, David Osborn, Christa Fittschen, Coralie Schoemaecker, Marius Duncianu, ASma Grira, Sebastien Dusanter, Alexandre Tomas, Carl Percival, Dudley Shallcross, Craig Taatjes

Research output: Contribution to journal › Article (Academic Journal)

15 Citations (Scopus)

249 Downloads (Pure)

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 (ISC) 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 the 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.

Original language	English
Article number	4343
Number of pages	9
Journal	Nature Communications
Volume	9
DOIs	https://doi.org/10.1038/s41467-018-06716-x
Publication status	Published - 19 Oct 2018

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Professor Dudley E Shallcross

D.E.Shallcross@bristol.ac.uk

School of Chemistry - Professor of Atmospheric Chemistry
Cabot Institute for the Environment
Spectroscopy and Dynamics
Atmospheric and Global Change Chemistry
Computational and Theoretical Chemistry
Atmospheric Chemistry

Person: Academic , Member

Cite this

Caravan, R., Khan, A., Zador, J., Sheps, L., Antonov, I., Rotavera, B., Ramasesha, K., Au, K., Chen, M-W., Rosch, D., Osborn, D., Fittschen, C., Schoemaecker, C., Duncianu, M., Grira, AS., Dusanter, S., Tomas, A., Percival, C., Shallcross, D., & Taatjes, C. (2018). The reaction of hydroxyl and methylperoxy radicals is not a major source of atmospheric methanol. Nature Communications, 9, [4343]. https://doi.org/10.1038/s41467-018-06716-x

Caravan, Rebecca ; Khan, Anwar ; Zador, Judit ; Sheps, Leonid ; Antonov, Ivan ; Rotavera, Brandon ; Ramasesha, Krupa ; Au, Kendrew ; Chen, Ming-Wei ; Rosch, Daniel ; Osborn, David ; Fittschen, Christa ; Schoemaecker, Coralie ; Duncianu, Marius ; Grira, ASma ; Dusanter, Sebastien ; Tomas, Alexandre ; Percival, Carl ; Shallcross, Dudley ; Taatjes, Craig. / The reaction of hydroxyl and methylperoxy radicals is not a major source of atmospheric methanol. In: Nature Communications. 2018 ; Vol. 9.

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title = "The reaction of hydroxyl and methylperoxy radicals is not a major source of atmospheric methanol",

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 (ISC) 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 the 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.",

author = "Rebecca Caravan and Anwar Khan and Judit Zador and Leonid Sheps and Ivan Antonov and Brandon Rotavera and Krupa Ramasesha and Kendrew Au and Ming-Wei Chen and Daniel Rosch and David Osborn and Christa Fittschen and Coralie Schoemaecker and Marius Duncianu and ASma Grira and Sebastien Dusanter and Alexandre Tomas and Carl Percival and Dudley Shallcross and Craig Taatjes",

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Caravan, R, Khan, A, Zador, J, Sheps, L, Antonov, I, Rotavera, B, Ramasesha, K, Au, K, Chen, M-W, Rosch, D, Osborn, D, Fittschen, C, Schoemaecker, C, Duncianu, M, Grira, AS, Dusanter, S, Tomas, A, Percival, C, Shallcross, D & Taatjes, C 2018, 'The reaction of hydroxyl and methylperoxy radicals is not a major source of atmospheric methanol', Nature Communications, vol. 9, 4343. https://doi.org/10.1038/s41467-018-06716-x

The reaction of hydroxyl and methylperoxy radicals is not a major source of atmospheric methanol. / Caravan, Rebecca; Khan, Anwar; Zador, Judit; Sheps, Leonid; Antonov, Ivan; Rotavera, Brandon; Ramasesha, Krupa; Au, Kendrew; Chen, Ming-Wei; Rosch, Daniel; Osborn, David; Fittschen, Christa; Schoemaecker, Coralie; Duncianu, Marius; Grira, ASma; Dusanter, Sebastien; Tomas, Alexandre; Percival, Carl; Shallcross, Dudley; Taatjes, Craig.

In: Nature Communications, Vol. 9, 4343, 19.10.2018.

Research output: Contribution to journal › Article (Academic Journal)

TY - JOUR

T1 - The reaction of hydroxyl and methylperoxy radicals is not a major source of atmospheric methanol

AU - Caravan, Rebecca

AU - Khan, Anwar

AU - Zador, Judit

AU - Sheps, Leonid

AU - Antonov, Ivan

AU - Rotavera, Brandon

AU - Ramasesha, Krupa

AU - Au, Kendrew

AU - Chen, Ming-Wei

AU - Rosch, Daniel

AU - Osborn, David

AU - Fittschen, Christa

AU - Schoemaecker, Coralie

AU - Duncianu, Marius

AU - Grira, ASma

AU - Dusanter, Sebastien

AU - Tomas, Alexandre

AU - Percival, Carl

AU - Shallcross, Dudley

AU - Taatjes, Craig

PY - 2018/10/19

Y1 - 2018/10/19

N2 - 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 (ISC) 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 the 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.

AB - 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 (ISC) 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 the 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.

U2 - 10.1038/s41467-018-06716-x

DO - 10.1038/s41467-018-06716-x

M3 - Article (Academic Journal)

C2 - 27748363

VL - 9

JO - Nature Communications

JF - Nature Communications

SN - 2041-1723

M1 - 4343

ER -