Abstract
This contribution investigates primary steps governing the OH-initiated atmospheric oxidation of CS2. Our approach comprises high-level density functional theory calculation of energies and optimisation of molecular structures as well as RRKM-ME analysis for estimating pressure-dependent reaction rate constants. We find the overall reaction OH + CS2→ OCS + SH too slow to account for the formation of the reported experimental products. The initial reaction of OH with CS2proceeds to produce an S-adduct, SCS(OH). Species-formation history for the system OH + CS2indicates that, the S-adduct represents the most plausible product with a barrier-less addition process and a stability amounting to 48.5 kJ/mol, in reference to the separated reactants. This adduct then undergoes a bimolecular reaction with atmospheric O2yielding OCS and HOSO, rather than dissociating back into its separated reactants. We also find that further atmospheric oxidation of the C-adduct (if formed) yields two of the major experimental products namely OCS and SO2. The kinetic analysis provided in this study explains the atmospheric fate of reduced sulfur species, an important S-bearing group in the global cycle of sulfur.
Original language | English |
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Pages (from-to) | 43-48 |
Number of pages | 6 |
Journal | Chemical Physics Letters |
Volume | 669 |
Issue number | February |
Early online date | 8 Dec 2016 |
DOIs | |
Publication status | Published - Feb 2017 |
Externally published | Yes |