Status of the OH contribution to the surface glow detected from the Dynamics Explorer satellite

A Fabry‐Perot interferometer on the DE‐2 satellite measured a surface glow near 732 nm at an altitude of 250 km. By comparison with the mesospheric nightglow, the hydroxyl radical (OH) was implicated as the fluorescing species. Unfortunately, the identification was not clear cut, since the spectrum showed an additional feature not observed in the nightglow. Calculations indicated that this feature could originate from ground state OH vibrational levels well above die energetic limit of v = 9 for the reaction of H + 0 3 . Until recently, existing spectroscopic data were inadequate for a positive identification of all the features in the Fabry‐Perot spectrum. New laboratory data coupled with accurate spectroscopic fitting indicate that the position of the additional feature is consistent with its identification as the P 2 (5) doublet of the (11,5) vibrational band of OH.