Infrared action spectroscopy of HOOO radical: Atmospheric reservoir for OH radical

PHYS 647

Erika L Derro, ederro@sas.upenn.edu, Craig Murray, crmurray@sas.upenn.edu, Timothy D. Sechler, sechler@sas.upenn.edu, and Marsha I Lester, milester@sas.upenn.edu. Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104
HOOO has been proposed as an intermediate in several important chemical reactions and relaxation processes involving OH in the atmosphere. HOOO is generated in a pulsed supersonic expansion by the association of O2 and photolytically generated OH radicals. Rotationally resolved infrared action spectra are obtained for trans-HOOO in the fundamental and overtone OH stretching regions, as well as for combination bands involving OH stretch with lower frequency modes, such as HOOO torsion, O-O-O bend, and the central O-O stretch. In addition, an unstructured feature is observed in both the OH fundamental and overtone regions of HOOO and is tentatively assigned to cis-HOOO. The highest energetically observed OH product channel following vibrational predissociation of HOOO sets an upper limit for the HO–O2 binding energy. The experimental stability of HOOO and derived equilibrium constant imply that a significant fraction of atmospheric OH may be converted into HOOO in the tropopause region.
 

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
8:00 PM-10:00 PM, Monday, April 7, 2008 Morial Convention Center -- Hall A, Sci-Mix

Division of Physical Chemistry

The 235th ACS National Meeting, New Orleans, LA, April 6-10, 2008