Abstract
The reaction of chlorine with alkaline hydrogen peroxide has been used to produce O2(a1 Δ g ) in a fast flow system at partial pressures up to about 0.5 Torr, and total pressures (mostly argon) in the range 0.8–2.5 Torr. Absolute concentrations of O2(a1 Δ g ) were determined from the intensity of absorption of hydrogen emission lines in the vacuum-UV at 144.095 and 148.66 nm, for which the cross sections are known. The intensity of the O2 (a → X) transition at 1270 nm, monitored simultaneously with a simple germanium detector, was found to vary linearly with [O2(a1 Δ g )], as expected. The germanium detector was calibrated at 1270 nm with a readily reproducible standard, the air afterglow continuum due to NO2* at defined concentrations of O(3P) and NO. The ratio of ka for O2(a) ka O 2 (X) + hvt to kc for O + NO kc NO2 + hv, is (1.4 ± 0.2) × 10−7 mol L−1 at 1270 nm.
Get full access to this article
View all access options for this article.
