A laser‐induced fluorescence determination of the internal state distribution of NO produced in the reaction: H+NO2→OH+NO

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Laser‐induced fluorescence (LIF) spectra have been recorded of NO produced when H atoms and NO2 react in thermal energy collisions in the region where two uncollimated jets containing the reagents intersect. Spectra of the (0,0), (1,1) and (2,2) bands and the (0,2) and (1,3) bands of the A 2Σ+–X 2Π γ‐band system have been observed. Distributions of NO over rovibrational levels have been determined by matching the experimental spectra to simulated spectra. The high J tail of the rotational distributions fit a linear surprisal plot. The analysis leads to average fractional yields of vibration and rotation energy, 〈fvib〉NO=0.056 and 〈frot〉NO=0.10, as well as branching ratios into vibrational (v=0–3), spin–orbit and Λ‐doublet states. Preferences are found for the lower 2Π1/2 spin–orbit substate and for the Π(A’) Λ‐doublet levels. Combined with results from the preceding paper, the data indicate that ∼31% of the energy released in the reaction should appear as relative translational motion of OH and NO. The reaction appears to proceed via the ground state HONO surface but the complex does not survive sufficiently long for complete energy randomisation: OH is more excited, NO less excited, than would be expected on a purely statistical basis.


Original languageEnglish
Pages (from-to)3187-3195
JournalJournal of Chemical Physics
Issue number5
Publication statusPublished - 1 Sep 1990