Estimation of rate coefficients and branching ratios for reactions of organic peroxy radicals for use in automated mechanism construction

• Main Authors: M. E. Jenkin, R. Valorso, B. Aumont, A. R. Rickard
• Format: Article
• Language: English
• Published: Copernicus Publications 2019-06-01
• Series: Atmospheric Chemistry and Physics
• Online Access: https://www.atmos-chem-phys.net/19/7691/2019/acp-19-7691-2019.pdf

<p>Organic peroxy radicals (<span class="inline-formula">RO₂</span>), formed from the degradation of hydrocarbons and other volatile organic compounds (VOCs), play a key role in tropospheric oxidation mechanisms. Several competing reactions may be available for a given <span class="inline-formula">RO₂</span> radical, the relative rates of which depend on both the structure of <span class="inline-formula">RO₂</span> and the ambient conditions. Published kinetics and branching ratio data are reviewed for the bimolecular reactions of <span class="inline-formula">RO₂</span> with NO, <span class="inline-formula">NO₂</span>, <span class="inline-formula">NO₃</span>, OH and <span class="inline-formula">HO₂</span>; and for their self-reactions and cross-reactions with other <span class="inline-formula">RO₂</span> radicals. This information is used to define generic rate coefficients and structure–activity relationship (SAR) methods that can be applied to the bimolecular reactions of a series of important classes of hydrocarbon and oxygenated <span class="inline-formula">RO₂</span> radicals. Information for selected unimolecular isomerization reactions (i.e. H-atom shift and ring-closure reactions) is also summarized and discussed. The methods presented here are intended to guide the representation of <span class="inline-formula">RO₂</span> radical chemistry in the next generation of explicit detailed chemical mechanisms.</p>