STABILIZATION OF THE PRIMARY PRODUCTS OF O((1)D) REACTIONS WITH CO, CO2, CH4, AND OTHER HYDROCARBONS IN CRYOGENIC MATRICES

Broad-band UV-visible irradiation of argon matrices containing 2% N2O and 10% of either CO, CO2, methane or ethane resulted in the formation Of CO2, CO3, CH3OH, or CH3CH2OH as the dominant photoproducts of O(1D) reactions, as observed by FTIR absorption spectroscopy. With methane, no significant production of formaldehyde or methyl or hydroxyl radicals was observed, in contrast with previous work on this system in liquid argon. Similar irradiation of argon matrices containing 2% N2O and 10% propane or isobutane gave rise to mixtures of 1-propanol and 2-propanol or 2-methyl-1-propanol and 2-methyl-2-propanol. The latter reaction showed an essentially statistically determined product ratio, indicating indiscriminate attack of O(1D) on the different C-H bonds of isobutane, as has been found in previous gas- and liquid-phase studies. Matrix-isolated NO, cis-ON-NO, ON-NO2, and NO2 were also observed as side products of the reactions of O(1D) with all precursor molecules. In all cases, no other major photoproducts or decomposition fragments were observed, indicating the occurrence of very efficient quenching of the highly energized primary reaction products.