15min:

MATTHEW K. SPRAGUE, MITCHIO OKUMURA, California Institute of Technology, Division of Chemistry, MC 127-72, Pasadena, CA 91125; AND STANLEY P. SANDER, Jet Propulsion Laboratory, California Institute of Technology, MS 183-901, Pasadena, CA 91109.

Alkoxy radicals are atmospherically important species, playing a direct role in the HO_x and NO_x cycles that affect tropospheric air pollution. Alkoxy radicals that can form a six membered transition state can isomerize into a hydroxyalkyl radical. In the presence of O₂, a rapid association reaction occurs, forming a hydroxyalkylperoxy radical. The n -butoxy radical is the smallest alkoxy to undergo isomerization, forming the -hydroxybutylperoxy radical (HOC₄H₈OO). Direct detection of HOC₄H₈OO opens the door to measuring alkoxy reaction kinetics with higher precision than previous end product studies.\footnoteR.~Atkinson, D.~L.~Baulch, R.~A.~Cox, J.~N.~Crowley, R.~F.~Hampson, R.~G.~Hynes, M.~E.~Jenkin, M.~J.~Rossi, and J.~Troe J. Atmos. Chem. and Phys. \textbf2006, 6 , 3625.

In this talk, we report the first detection of the Ã-X electronic spectrum of the HOC₄H₈OO radical. The spectrum is similar in shape to the Ã-X spectrum of n -butyl peroxy:\footnoteB.~G.~Glover and T.~A.~Miller. J. Phys. Chem. A \textbf2005, 109 , 11191. a broad spectroscopic band due to the multiple molecular conformers that are present. We also use the Ã-X band to measure the alkoxy isomerization kinetics relative to the alkoxy radical's reaction with O₂, similar to the previous kinetics studies.