INDIRECT MECHANISM FOR THE PRODUCTION OF O(S-1) IN THE AURORA

Recent laboratory measurements of the deactivation rate constants for O(1S) have suggested that the dominant production mechanism for the green line in the nightglow is a two-step process. A similar mechanism involving energy transfer from an excited state of molecular oxygen is considered as a potential source of the OI (5577 Å) emission in the aurora. It is shown that the mechanism, O2 + e → O2 * + e O2 * + O → O2 + O(1S), is consistent with auroral observations; the intermediate excited state has been tentatively identified as the O2(c1∑- u) state. For the proposed energy transfer mechanism to be the primary source of the auroral green line, the peak electron impact cross-section for O2 * production must be approximately 2 × 10-17 cm2. © 1979.