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Reactions between Criegee Intermediates and the Inorganic Acids HCl and HNO 3 : Kinetics and Atmospheric Implications
Author(s) -
Foreman Elizabeth S.,
Kapnas Kara M.,
Murray Craig
Publication year - 2016
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201604662
Subject(s) - chemistry , reaction rate constant , radical , kinetics , water vapor , photochemistry , atmospheric chemistry , chemical kinetics , inorganic chemistry , chemical reaction , computational chemistry , organic chemistry , ozone , physics , quantum mechanics
Abstract Criegee intermediates (CIs) are a class of reactive radicals that are thought to play a key role in atmospheric chemistry through reactions with trace species that can lead to aerosol particle formation. Recent work has suggested that water vapor is likely to be the dominant sink for some CIs, although reactions with trace species that are sufficiently rapid can be locally competitive. Herein, we use broadband transient absorption spectroscopy to measure rate constants for the reactions of the simplest CI, CH 2 OO, with two inorganic acids, HCl and HNO 3 , both of which are present in polluted urban atmospheres. Both reactions are fast; at 295 K, the reactions of CH 2 OO with HCl and HNO 3 have rate constants of 4.6×10 −11 cm 3 s −1 and 5.4×10 −10 cm 3 s −1 , respectively. Complementary quantum‐chemical calculations show that these reactions form substituted hydroperoxides with no energy barrier. The results suggest that reactions of CIs with HNO 3 in particular are likely to be competitive with those with water vapor in polluted urban areas under conditions of modest relative humidity.