Generation of high O2 (a1Δg) concentrations in O2/H2 mixtures

The effect of hydrogen on the concentration of singlet oxygen in the a¹Δ_g and b¹Σ states, generated from a microwave discharge in O₂ and in an O₂/Ar mixture, was studied in flow reactors. The addition of hydrogen, in a range of 0.01–1 of concentration of the O₂, increased the yields of singlet oxygen by factor of 5–20. In addition to the higher O₂ (a and b) concentrations, the addition of hydrogen removed the usual NO₂ fluorescence, making observation of the O₂(b → X) transition at 762 nm much easier in the flow reactor. © 2005 Wiley Periodicals, Inc. Int J Chem Kinet 38: 12–17, 2006