The influence of metastable oxygen molecules on ozone and airglow

Recent laboratory studies [Mathias and Schiff, 1964; Kaufman and Kelso, 1964; Bader and Ogryzlo, 1964] have indicated that oxygen molecules in the two lowest electronically excited states (1Δg and 1Σg+) are capable of decomposing ozone by the process O2*+O3→O2+O2+O k23 Mathias and Schiff [1964] found the rate constant for this reaction to be 1.7 times that of the reaction O+O3→O2+O2 k13 Reaction 1 may therefore play an important role in determining the O3 concentration in the atmosphere. The best evidence for the existence of these molecules in the atmosphere comes from the observed radiations characteristic of these species. It has long been known [Meinel, 1950] that the (0, 1) band of the (1Σg+ − 3Σg−) system of oxygen appears in the night airglow spectrum with an intensity of about 1.5 kilorayleighs. The (0, 0) band is absorbed in the lower atmosphere but should have an intensity of nearly 150 kilorayleighs [Noxon, 1961] which corresponds to about 1012 O2.(1Σg*) molecules cm−2 column. This value is even larger if deactivation occurs. The height has not been well established, but the rotational temperature is about 150°K, which places the layer at about 85 km. The excitation capable of explaining its long nighttime duration is not yet understood. There are no observations on the behavior of this emission in the daytime and no strong twilight enhancements have been reported.