O(¹S) FROM DISSOCIATIVE RECOMBINATION OF O₂ ⁺: NONTHERMAL LINE PROFILE MEASUREMENTS FROM DYNAMICS EXPLORER.

Direct measurements at high spectral resolution of the O(**1S) emission line profile at 5577 A made using the Fabry-Perot interferometer on Dynamics Explorer are reported. The line profile is found to have marked nonthermal characteristics in the nightglow. The nighttime emission line profiles, measured in the equatorial region, have been analyzed using a simple collisional relaxation model. The branching ratio for the dissociative recombination of O//2** plus leading to O(**1S) is inferred. The result shows that the O(**1S) plus O(**1D) channel is favored over the O(**1S) plus O(**3P) channel by a factor of 4.