The O I (λ5577 Å) airglow: Observations and excitation mechanisms

Abstract

Analysis of the O I (λ5577 A) airglow observations conducted on board the Atmosphere Explorer C satellite yields the following results when combined with simultaneous measurements of ion and neutral composition. A volume emission rate profile derived after sunset requires the production of an O(¹S) atom in 8% of the O2+ recombinations. Photoelectron impact on atomic oxygen and the dissociative recombination of O2+ are important sources of O(¹S) in the dayglow; however, the airglow measurements require a large additional production of O(¹S) below 200 km in addition to these. The reaction N + O2+ → NO+ + O(¹S) can provide the missing O(¹S) source if the rate coefficient is near 2.5 × 10−11 cm³ s−1.