Effect of a single water molecule on the HO2 + ClO reaction. Issue 16 (29th September 2017)

• Record Type: Journal Article
• Authors: Li, Junyao; Tsona, Narcisse T.; Du, Lin
• Is Part Of: Physical chemistry chemical physics. Volume 20:Issue 16(2018)
• Page Start: 10650
• Page End: 10659
• Publication Date: 2017-09-29
• Subjects: Chemistry, Physical and theoretical -- Periodicals; 541.3
• DOI: 10.1039/c7cp05008a
• Languages: English
• ISSNs: 1463-9076

Abstract

Abstract : The presence of a single water molecule retards the reaction of HO2 with ClO. Abstract : The catalytic effect of a single water molecule on the HO2 + ClO reaction has been investigated at the CCSD(T)/aug-cc-pVTZ//B3LYP-D3/aug-cc-pVDZ level of theory. Four H-abstraction paths and two kinds of products, among which the paths for HOCl + O2 formation are dominant, have been found for the HO2 + ClO reaction without water. The rate constant of the most favorable path for the reaction without water is computed to be 4.53 × 10 −12 cm 3 molecule −1 s −1 at room temperature, in good agreement with the experiment. In the presence of a water molecule, although the reaction becomes more complex, the dominant products do not change. Four main channels, starting from HO2 ⋯H2 O + ClO, H2 O⋯HO2 + ClO, ClO⋯H2 O + HO2 and H2 O⋯ClO + HO2, are investigated. The most favorable paths, reactions between H2 O⋯HO2 and ClO, and between ClO⋯H2 O and HO2, are 7–10 and 6–9 orders of magnitude slower than the reaction in the absence of water, respectively. It is concluded that the presence of a single water molecule does not play an important role in enhancing the HO2 + ClO reaction under tropospheric conditions.