Excimer Laser Fragmentation Studies of Selected Oximes: Nascent OH internal Energy Distributions and the Search of H2CN Fluorescence
ARMY BALLISTIC RESEARCH LAB ABERDEEN PROVING GROUND MD
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Excimer laser excitation 193 nm of formaldoxime H2 CN-OH or the methylated homologs, R2R2CH-OH where R1, R2 H or CH3, results in dissociation. The upper limit for the quantum yield of fluorescence of the R1R2CN is estimated to be between 1-10 depending on the precursor used. The OH companion radical was probed by laser induced fluorescence LIF utilizing the A-X 2-1 and 1,0 bands near 34700 cm-1, and the nascent rotational, vibrational, and ground electronic state spin-orbit distributions determined. No laser induced fluorescence of the R1R2CN radical could be observed upon irradiation in the regions where the radicals are known to absorb, 280 to 295 nm. From the nascent OH product distributions, we calculate that only 2.5 Kcalmole of the excess energy appears as OH product internal energy, thus leaving about 80 Kcalmole to be divided between the R1R2CN fragment and translation. We, therefore, conclude that it is highly likely that the upper states of these radicals probed in the 280 to 295 nm region are predissociative.
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