The OI(¹S) state: Its quenching by O₂ and formation by the dissociative recombination of vibrationally excited O₂⁺ ions

The rate coefficient for the quenching of metastable O(¹S) atoms by O 2 has been measured as a function of temperature from 250°K to 550°K. The resulting Arrhenius expressionk 1 = 4.9 × 10 −12 exp[‐(885 ± 35)/T]is in good agreement with previous laboratory work. It is suggested that the much larger value for k 1 inferred from an analysis of the artificial auroral experimentPrecedeis due to overestimating the contribution to O(¹S) production from O 2 + dissociative recombination. The possibility that O(¹S) atoms are produced only by the dissociative recombination of vibrationally excited O 2 + ions is discussed; such excited ions would not exist at the altitude of the Precede experiment because of the rapid cooling of these ions by resonant charge transfer processes.