HR: 17:30h
AN: A24B-07 [Abstracts]
TI: Ozonolysis and Subsequent Photolysis of unsaturated organic molecules: Model Systems for Photochemical
Aging of Organic Aerosol Particles
AU: * Park, J
EM: jihop@uci.edu
AF: Department of Chemistry
University of California at Irvine, 590 Rowland Hall, Irvine, CA 92697
United States
AU: Gomez, A L
A24B-07
AF: Department of Chemistry
University of California at Irvine, 590 Rowland Hall, Irvine, CA 92697
United States
AU: Walser, M L
A24B-07
AF: Department of Chemistry
University of California at Irvine, 590 Rowland Hall, Irvine, CA 92697
United States
AU: Lin, A
A24B-07
AF: Department of Chemistry
University of California at Irvine, 590 Rowland Hall, Irvine, CA 92697
United States
AU: Nizkorodov, S A
EM: nizkorod@uci.edu
AF: Department of Chemistry
University of California at Irvine, 590 Rowland Hall, Irvine, CA 92697
United States
AB:
Chemical and photochemical aging of organic species adsorbed on aerosol particle surfaces is believed to have a significant
effect on cloud condensation properties of atmospheric aerosols. Ozone initiated oxidation reactions of thin films of
undecylenic acid and alkene-terminated self assembled monolayers (SAMs) on SiO2 surface were investigated using a combination
of spectroscopic and mass spectrometric techniques. Photolysis of the oxidized film in the tropospheric actinic region
(λ>290 nm) readily produces formaldehyde and formic acid as gas-phase products. Photodissociation action spectra of
the oxidized film suggest that organic peroxides are responsible for the enhanced photochemical activity. The presence of
peroxides in the oxidized sample was confirmed by mass-spectrometric analysis and by an iodometric test. Significant
polymerization resulting from secondary reactions of Criegee radicals during ozonolysis of the film is also observed. The
reaction mechanism and its implications for photochemical aging of atmospheric aerosol particles will be discussed.
DE: 0305 Aerosols and particles (0345, 4801, 4906)
SC: Atmospheric Sciences [A]
MN: Fall Meeting 2005