Title: Direct kinetic measurement of the reaction of the simplest Criegee intermediate with water vapor
Authors: Chao, Wen
Hsieh, Jun-Ting
Chang, Chun-Hung
Lin, Jim Jr-Min
Department of Applied Chemistry
Issue Date: 13-Feb-2015
Abstract: Carbonyl oxides, or Criegee intermediates, are important transient species formed in the reactions of unsaturated hydrocarbons with ozone. Although direct detection of Criegee intermediates has recently been realized, the main atmospheric sink of Criegee intermediates remains unclear. We report ultraviolet absorption spectroscopic measurements of the lifetime of the simplest Criegee intermediate, CH2OO, at various relative humidity levels up to 85% at 298 kelvin. An extremely fast decay rate of CH2OO was observed at high humidity. The observed quadratic dependence of the decay rate on water concentration implied a predominant reaction with water dimer. On the basis of the water dimer equilibrium constant, the effective rate coefficient of the CH2OO + (H2O)(2) reaction was determined to be 6.5 (+/-0.8) x 10(-12) cubic centimeters per second. This work would help modelers to better constrain the atmospheric concentrations of CH2OO.
URI: http://dx.doi.org/10.1126/science.1261549
ISSN: 0036-8075
DOI: 10.1126/science.1261549
Journal: SCIENCE
Volume: 347
Issue: 6223
Begin Page: 751
End Page: 754
Appears in Collections:Articles