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Kinetic and theoretical investigations of the S + NO2 reaction

Authors

  • Kristopher M. Thompson,

    1. Department of Chemistry and Center for Advanced Scientific Computing and Modeling, University of North Texas, Denton, TX 76203-5017
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  • Yide Gao,

    1. Department of Chemistry and Center for Advanced Scientific Computing and Modeling, University of North Texas, Denton, TX 76203-5017
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  • Paul Marshall

    Corresponding author
    1. Department of Chemistry and Center for Advanced Scientific Computing and Modeling, University of North Texas, Denton, TX 76203-5017
    • Department of Chemistry and Center for Advanced Scientific Computing and Modeling, University of North Texas, Denton, TX 76203-5017
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Abstract

Ground state atomic sulfur was generated by 193-nm laser photolysis of CS2 precursor in Ar bath gas, in the presence of a large excess of NO2 under pseudo-first-order conditions. Decays of S(3PJ) were monitored over 292–656 K and pressures of 14–535 mbar. No pressure dependence was observed, and the second-order constants are summarized as k(T) = 1.9 × 10−11 exp(+4.1 kJ mol−1)/RT cm3 molecule−1 s−1, with a 95% confidence interval of ±7%. The potential energy surfaces for SNO2 and S(NO2)2 were explored using QCISD/6-311G(d,p) theory for geometries and frequencies, followed by single-point calculations based on coupled-cluster theory and extrapolation of results with cc-pV(T+d)Z and cc-pV(Q+d)Z basis sets to the complete basis set limit. Corrections were made for scalar relativistic effects and core–valence correlation. A mechanism involving initial barrierless addition of S to the N atom in NO2, followed by fast dissociation to SO + NO, is consistent with the observed lack of pressure dependence and a Rice–Ramsperger–Kassel–Marcus estimate of the dissociation rate of SNO2 compared to collisional stabilization. © 2011 Wiley Periodicals, Inc. Int J Chem Kinet 44: 90–99, 2012

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