15min:

DAVID T. ANDERSON, KYLIE A. KUFELD, DOMINIQUE SCHOECH, ROBERT B. SLIPP AND FARAJ M. ALMARRI, Department of Chemistry, University of Wyoming, Laramie, WY 82071-3838.

Our group is studying the 193.3 nm photochemistry of methanol (CH₃OH) isolated in solid pH₂ using high-resolution FTIR spectroscopy to explore the low temperature reactions of H-atoms with CH₃OH. Gas phase studies have shown that the dominant photodissociation channel is CH₃OH + h CH₃O + H, and thus the in situ photochemistry is expected to produce methoxy and H-atom radicals. After photolysis the methoxy radicals are immobilized at these temperatures, but the H-atoms can still readily move through solid pH₂. For short time 193.3 nm exposures, greater than 90% of the CH₃OH remains intact and therefore repeated FTIR spectra immediately after photolysis can be used to record the kinetics of reactions of H-atoms with CH₃OH. We observe exponential growth in the intensities of a number of peaks that can be assigned to the hydroxymethyl CH₂OH radical. Further, the growth is bi-exponential and we believe there are two processes that lead to the formation of CH₂OH: (1) fast growth by interconversion of CH₃O to CH₂OH and (2) slow growth due to hydrogen abstraction reactions of cold H-atoms with CH₃OH. We have not observed the methoxy radical. Currently we are performing photochemical experiments on fully deuterated methanol (CD₃OD) in solid pH₂ to test these kinetic interpretations, and the most recent results and analysis will be presented.