On adduct formation and reactivity in the OCS + OH reaction: A combined theoretical and experimental study

Johan A. Schmidt*, Mildrid Kyte, Freja F. Østerstrøm, Lars M.T. Joelsson, Hasse C. Knap, Solvejg Jørgensen, Ole John Nielsen, Tatsuhiro Murakami, Matthew S. Johnson

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


The OCS + OH reaction occurs either via adduct formation or direct S-abstraction. We investigate OH-oxidation of OCS using quantum chemical methods and find that the OC(OH)S adduct reacts rapidly with O2 forming SOOH + CO2. SOOH rapidly dissociates under atmospheric conditions regenerating OH. We interpret earlier experimental results based on monitoring OH-loss, and find that OH-regeneration in presence of O2 may explain the insensitivity of the reaction rate to pressure and O2. We calculate a rate constant of 3.52×10-16 cm3 s−1 at 10 Torr increasing to 7.20×10-16 cm3 s−1 at 700 Torr. In addition we present a new experimental determination of the OCS + OH rate constant of (5.3±3.6)×10-15 cm3 s−1 at 296  and 700 Torr using relative-rate technique.

Original languageEnglish
Pages (from-to)111-117
Number of pages7
JournalChemical Physics Letters
Early online date6 Mar 2017
Publication statusPublished - May 2017


  • Computational chemistry
  • Kinetics
  • OCS
  • OH
  • Relative rate
  • SOOH

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