Atmospheric Fate of the CH3SOO Radical from the CH3S + O2Equilibrium
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Atmospheric Fate of the CH3SOO Radical from the CH3S + O2Equilibrium. / Chen, Jing; Berndt, Torsten; Møller, Kristian H.; Lane, Joseph R.; Kjaergaard, Henrik G.
I: Journal of Physical Chemistry A, Bind 125, Nr. 40, 14.10.2021, s. 8933-8941.Publikation: Bidrag til tidsskrift › Tidsskriftartikel › Forskning › fagfællebedømt
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TY - JOUR
T1 - Atmospheric Fate of the CH3SOO Radical from the CH3S + O2Equilibrium
AU - Chen, Jing
AU - Berndt, Torsten
AU - Møller, Kristian H.
AU - Lane, Joseph R.
AU - Kjaergaard, Henrik G.
N1 - Publisher Copyright: © 2021 American Chemical Society
PY - 2021/10/14
Y1 - 2021/10/14
N2 - The atmospheric oxidation mechanisms of reduced sulfur compounds are of great importance in the biogeochemical sulfur cycle. The CH3S radical represents an important intermediate in these oxidation processes. Under atmospheric conditions, CH3S will predominantly react with O2to form the peroxy radical CH3SOO. The formed CH3SOO has two competing unimolecular reaction pathways: isomerization to CH3SO2, which further decomposes into CH3and SO2, or a hydrogen shift followed by HO2loss, leading to CH2S. Previous theoretical calculations have suggested that CH2S formation should be the dominant pathway, in disagreement with existing experimental results. Our large active space multireference configuration interaction calculations agree with the experimental results that the formation of CH3and SO2is the dominant route and the formation of CH2S and HO2can, at most, be a minor pathway. We support the calculations with new experiments starting from the OH + CH3SH reaction for CH3S formation under low NOxconditions and find a SO2yield of 0.86 ± 0.18 within our reaction time of 7.9 s. Model simulations of our experiments show that the SO2yield converges to 0.98. This combined theoretical and experimental study thus furthers the understanding of the general oxidation mechanisms of sulfur compounds in the atmosphere.
AB - The atmospheric oxidation mechanisms of reduced sulfur compounds are of great importance in the biogeochemical sulfur cycle. The CH3S radical represents an important intermediate in these oxidation processes. Under atmospheric conditions, CH3S will predominantly react with O2to form the peroxy radical CH3SOO. The formed CH3SOO has two competing unimolecular reaction pathways: isomerization to CH3SO2, which further decomposes into CH3and SO2, or a hydrogen shift followed by HO2loss, leading to CH2S. Previous theoretical calculations have suggested that CH2S formation should be the dominant pathway, in disagreement with existing experimental results. Our large active space multireference configuration interaction calculations agree with the experimental results that the formation of CH3and SO2is the dominant route and the formation of CH2S and HO2can, at most, be a minor pathway. We support the calculations with new experiments starting from the OH + CH3SH reaction for CH3S formation under low NOxconditions and find a SO2yield of 0.86 ± 0.18 within our reaction time of 7.9 s. Model simulations of our experiments show that the SO2yield converges to 0.98. This combined theoretical and experimental study thus furthers the understanding of the general oxidation mechanisms of sulfur compounds in the atmosphere.
U2 - 10.1021/acs.jpca.1c06900
DO - 10.1021/acs.jpca.1c06900
M3 - Journal article
C2 - 34601880
AN - SCOPUS:85117213746
VL - 125
SP - 8933
EP - 8941
JO - Journal of Physical Chemistry Part A: Molecules, Spectroscopy, Kinetics, Environment and General Theory
JF - Journal of Physical Chemistry Part A: Molecules, Spectroscopy, Kinetics, Environment and General Theory
SN - 1089-5639
IS - 40
ER -
ID: 285308099