Journal article
The kinetics study of the S + S2 → S3 reaction by the chaperone mechanism
The Journal of chemical physics, Vol.134(15), pp.154508-154508
04/21/2011
Handle:
https://hdl.handle.net/2376/114408
PMID: 21513396
Abstract
The recombination of S atoms has been found to be stepwise from the smallest unit, the elemental S atom, to the most abundant molecule S(8). The reaction between S + S(2) → S(3) has not been reported either experimentally or by theory, but may be a key intermediate step in the formation of sulfur aerosols in low-O(2) atmospheres. In this work, the kinetics of this reaction is reported with Ar gas used as the chaperone molecule in the production of S(3) via two complex intermediates: SAr + S(2) and S(2)Ar + S. Quasi-classical and classical trajectory methods are used. The rate constant of the S + S(2) + Ar → S(3) + Ar reaction is determined to be 2.66 × 10(-33) cm(6) mol(-1) s(-1) at 298.15 K. The temperature dependence of the reaction is found to be 2.67 × 10(-33) exp[143.56(1∕T-1∕298.15)]. The second-order rate constant of S + S(2) → S(3) is 6.47 × 10(-14) cm(3) molecule(-1) s(-1) at 298.15 K and the Arrhenius-type rate constant is calculated to be 6.25 × 10(-14) exp[450.15(1∕T-1∕298.15)] cm(3) molecule(-1) s(-1). This work provides a rate coefficient for a key intermediate species in studies of sulfur formation in the modern Venus atmosphere and the primitive Earth atmosphere, for which assumed model rate coefficients have spanned nearly 4 orders of magnitude. Although a symmetry-induced mass-independent isotope effect is not expected for a chaperone mechanism, the present work is an important step toward evaluating whether mass-independence is expected for thiozone formation as is observed for ozone formation.
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Details
- Title
- The kinetics study of the S + S2 → S3 reaction by the chaperone mechanism
- Creators
- Shiyu Du - Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USATimothy C GermannJoseph S FranciscoKirk A PetersonHua-Gen YuJames R Lyons
- Publication Details
- The Journal of chemical physics, Vol.134(15), pp.154508-154508
- Academic Unit
- Chemistry, Department of
- Publisher
- United States
- Identifiers
- 99900547606901842
- Language
- English
- Resource Type
- Journal article