Kinetics of O2(1Σg+) Reaction with H2 and an Upper Limit for OH Production

The rate coefficients for the removal of O 2 ( 1 ) (from now on referred to as O 2 ( 1 Σ)) by H 2 were measured between 209 and 373 K by generating O 2 ( 1 Σ) via pulsed laser excitation near 762 nm. The rate coefficient was determined to be k 1 = (6.8 ± 1.2) × 10 -12 exp[−(590 ± 52)/ T ] cm 3 molecule -1 s -1 . Reaction of O 2 ( 1 Σ) with O 3 yielded O( 3 P), which was detected by vacuum ultraviolet (VUV)-resonance fluorescence. O 2 ( 1 Σ) was also prepared by the interaction of O( 1 D) with O 2 . In separate experiments, the yield for OH from the title reaction was measured to be <4 × 10 -5 at 298 and 209 K. This upper limit was used in a one-dimensional atmospheric model to show that the contribution of this reaction to the total OH production in the atmosphere is minimal under most conditions.