Estimation of mechanistic parameters in the gas-phase reactions of ozone with alkenes for use in automated mechanism construction

TY - JOUR

T1 - Estimation of mechanistic parameters in the gas-phase reactions of ozone with alkenes for use in automated mechanism construction

AU - Newland, Mike

AU - Mouchel-Vallon, Camille

AU - Valorso, Richard

AU - Aumont, Bernard

AU - Vereecken, Luc

AU - Jenkin, Michael E.

AU - Rickard, Andrew Robert

N1 - © Author(s) 2022

PY - 2022/5/11

Y1 - 2022/5/11

N2 - Reaction with ozone is an important atmospheric removal process for alkenes. The ozonolysis reaction produces carbonyls and carbonyl oxides (Criegee intermediates, CI), which can rapidly decompose to yield a range of closed shell and radical products, including OH radicals. Consequently, it is essential to accurately represent the complex chemistry of Criegee intermediates in atmospheric models in order to fully understand the impact of alkene ozonolysis on atmospheric composition. A mechanism construction protocol is presentedwhich is suitable for use in automatic mechanism generation. The protocol defines the critical parameters for describing the chemistry following the initial reaction, namely the primary carbonyl/CI yields from the primary ozonide fragmentation, the amount of stabilisation of the excited CI, the unimolecular decomposition pathways, rates and products of the CI, and the bimolecular rates and products of atmospherically important reactions of the stabilised CI (SCI). This analysis implicitly predicts the yield of OH from the alkene–ozone reaction. A comprehensive database of experimental OH, SCI and carbonyl yields has been collated using reported values in the literature and used to assess the reliability of the protocol. The protocol provides estimates of OH, SCI and carbonyl yields with root mean square errors of 0.13 and 0.12 and 0.14, respectively. Areas where new experimental and theoretical data would improve the protocol and its assessment are identified and discussed.

AB - Reaction with ozone is an important atmospheric removal process for alkenes. The ozonolysis reaction produces carbonyls and carbonyl oxides (Criegee intermediates, CI), which can rapidly decompose to yield a range of closed shell and radical products, including OH radicals. Consequently, it is essential to accurately represent the complex chemistry of Criegee intermediates in atmospheric models in order to fully understand the impact of alkene ozonolysis on atmospheric composition. A mechanism construction protocol is presentedwhich is suitable for use in automatic mechanism generation. The protocol defines the critical parameters for describing the chemistry following the initial reaction, namely the primary carbonyl/CI yields from the primary ozonide fragmentation, the amount of stabilisation of the excited CI, the unimolecular decomposition pathways, rates and products of the CI, and the bimolecular rates and products of atmospherically important reactions of the stabilised CI (SCI). This analysis implicitly predicts the yield of OH from the alkene–ozone reaction. A comprehensive database of experimental OH, SCI and carbonyl yields has been collated using reported values in the literature and used to assess the reliability of the protocol. The protocol provides estimates of OH, SCI and carbonyl yields with root mean square errors of 0.13 and 0.12 and 0.14, respectively. Areas where new experimental and theoretical data would improve the protocol and its assessment are identified and discussed.

KW - Ozonolysis

KW - Criegee intermediates

KW - Master Chemical Mechanism

KW - Atmospheric Chemistry

KW - Modelling

U2 - 10.5194/acp-22-6167-2022

DO - 10.5194/acp-22-6167-2022

M3 - Article

SN - 1680-7316

VL - 22

SP - 6167

EP - 6195

JO - Atmospheric Chemistry and Physics

JF - Atmospheric Chemistry and Physics

ER -