Computational studies on metathetical and redox processes of HOCl in the gas phase. 1. Reactions with H, O, HO, and HO2.
The potential energy surfaces of four reactions including (a) HOCl + H, (b) HOCl + O, (c) HOCl + HO, (d) HOCl + HO(2), have been studied by the CCSD(T)/aug-cc-pVTZ//CCSD/aug-cc-pVDZ, CCSD(T)/aug-cc-pVTZ//CCSD/cc-pVDZ, and CCSD(T)/6-311+G(3df,2p)//BH&HLYP/6-311+G(3df,2p) levels of theory. For both HOCl + H and HOCl + O, the direct Cl-abstraction channels take place via the lowest energy barriers; for both HOCl + HO and HOCl + HO(2), the lowest energy barrier channels are the indirect H-abstraction reactions by HO(x) (x = 1, 2) via long-lived reaction intermediates. The rate constants for the low barrier channels have been calculated in the temperature range 200-3000 K by statistical theory. The predicted rate constants for HOCl + H and HOCl + HO are in good agreement with experimental results whereas that for HOCl + O was found to be in disagreement with the majority of available experimental data, suggesting a need for further improvement in theory and/or experiment.
Xu
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Department of Chemistry, Emory University, Atlanta, Georgia 30322, USA.
Lin
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MC