Reaction Rate Measurements of O(3P) Atoms by Resonance Fluorescence. I O(3P)+O2+M→O3+M and O(3P)+NO+M→NO2+M

Abstract

Atomic resonance fluorescence techniques have been applied to the determination of O(3 P) atoms. The atoms were produced by O2photodissociation at 1470 Å and then detected by their scattering of 1302–1306‐Å oxygen resonance radiation, which was measured photoelectrically. By pulsing the photodissociation lamp, it was possible to make absolute measurements of the O(3 P) loss rate. To demonstrate the usefulness of the technique, rate constants at 300°K were determined for two three‐body reactions, O(3 P)+O2+M→O3+M for M is Ar and N2 (k Ar = 4.4 ± 0.6 × 10 −34 cm 6 molecules −2 · sec −1 , k N 2 = 7.0 ± 1.0 × 10 −34 cm 6 molecules −2 · sec −1 ) and O(3 P)+NO+Ar→NO2+Ar. For the latter reaction, a value of 13.5 × 10−32 cm6 molecules−2·sec−1 is obtained, which is precisely twice the accepted value. A possible explanation may involve very rapid reaction of the vibrationally excited NO2 product with a second O(3 P) atom.