This paper reports determinations of collisional deactivation rate constants for O2(1Δg) by minor atmospheric constituents and other gases. The benzene–oxygen photochemical system was used to produce O2(1Δg), and relative concentrations were measured by monitoring the intensity of its emission at 1.27 μ. The rate constants for the reaction O2(1Δg)+M→O2+M were 4.53 × 10−18, 5.60 × 10−18, and (0.5–1.0) × 10−19 (cm3 molecule−1·sec−1) for M=H2, H2O, and N2O, respectively. Upper limits were obtained for deactivation by He, Ar, CO2, and SF6 of 8.0 × 10−21, 8.3 × 10−21, 1.5 × 10−20, and 1.2 × 10−20, respectively. The temperature dependence of the deactivation of O2(1Δg) by oxygen has been investigated. The rate constant can be expressed in the form kO2 = 2.22 ± 0.09 × 10−18 (T / 300)n, where n = 0.78 ± 0.32 and T is the temperature in degrees Kelvin.

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The emission bands at 6 340 Å and 7 030 Å in the spectrum of excited molecular oxygen, believed to be due to the "dimol" O4*(1Δg, 1Δg), have been investigated with respect to the dependence of their intensities on the excited oxygen concentration. The intensities of these bands have been shown, by a comparison with the intensity of the (0,0) band of the (1Δg – 3Σg−) system at 12 700 Å, to depend on the square of the O2(1Δg) concentration. The ratio of the intensities of the two visible bands at 6 340 Å and 7 030 Å was found to be 1.05 ± 0.1.An attempt was made to resolve the 6 340 Å and 12 700 Å bands into their rotational fine structure. The results show that, whereas the 12 700 Å band could be at least partially resolved, the 6 340 Å band appeared to be diffuse with a band half-width of 150 Å.Evidence is presented of vibrational excitation in the 1Σg+ state of molecular oxygen in the discharged products.

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