DAVID T. ANDERSON AND FREDRICK M. MUTUNGA, Department of Chemistry, University of Wyoming, Laramie, WY 82071-3838.
We report on the results of chemical reactions of H-atoms with N2O in solid parahydrogen matrices investigated by rapid scan FTIR. The reaction is initiated by the 193 nm in situ photodissociation of N2O to produce N2 + O(1D). We assume the O(1D) photoproduct reacts with the parahydrogen host to create H-atoms. What we observe is growth of cis-HNNO right after photolysis is stopped along with a later delayed growth in trans-HNNO. We assign our peaks by comparison with a previous Xe matrix isolation study and recent ab initio calculations of the anharmonic vibrational frequencies and isotopic shifts. We performed some experiments using the 15N2 18O precursor molecule. Detailed study of the reaction kinetics indicate that at 1.8 K the cis-isomer is formed exclusively by the reaction, but then converts to the lower energy trans-isomer with time. These results are surprising because a 40 kJ/mol barrier is predicted for the H + N2O reaction, yet the reaction readily proceeds even at 1.8 K. We are currently studying this reaction under a variety of conditions and the most current results and analysis will be presented.