PHYS 637 |
| Photochemical reaction can be promoted through vibrational excitation of molecules in the ground electronic state using solar red photons. Recently shown as a viable process in atmospheric chemistry, this overtone-induced chemistry is drastically different from traditional UV photochemistry. Organic acids and alcohols are formed in the atmosphere through the oxidation of hydrocarbons and are implicated in nucleation of aerosols and clouds and secondary organic aerosol formation. Sunlight initiated chemistry could affect aerosol processing and aerosols' effectiveness as cloud condensation nuclei. In this study overtone intensities of two chromophores common to many atmospheric targets, SH and OH, have been compared in order to reveal their effectiveness in overtone chemistry. The specific model studied in detail is vinylacetic acid in the mid-infrared and near-infrared. A combination of experimental studies and theoretical calculations to investigate OH stretching levels near the barrier to decarboxylation. The spectroscopy studied sets the ground work for understanding photochemical decarboxylation of atmospheric acids. |
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PHYS Poster Session - Physical Chemistry of Atmospheric Processes
7:30 PM-10:00 PM, Wednesday, April 9, 2008 Morial Convention Center -- Hall A, Poster
Sci-Mix
Division of Physical Chemistry |