# $O_{2}(c^{1}\sum^{-}_{u}-b^{1}\sum^{+}_{g})$ BAND EMISSION IN THE TERRESTRIAL NIGHTGLOW

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 Title: $O_{2}(c^{1}\sum^{-}_{u}-b^{1}\sum^{+}_{g})$ BAND EMISSION IN THE TERRESTRIAL NIGHTGLOW Creators: Huestis, D. L.; Cosby, P. C.; Slanger, T. G. Issue Date: 2002 Abstract: Understanding of the spectroscopy of molecular oxygen has benefited from many investigations of the absorption and emission spectra from planetary atmospheres, a number of which we have described previously at this symposium. In the process of line-by-line assignment of sky spectra'' recorded by astronomers using the Keck I and II telescopes, we have discovered a new $O_{2}$ band system in the 380-450 nm region of the Earth's nightglow spectrum. Sharp isolated lines are assigned to the single Q-branch of $O_{2}(c^{1}\sum^{-}_{u},v^{\prime}=5-11)$ radiating to $O_{2}(b^{1}\sum^{+}_{g}, v^{\prime\prime}=0-2)$, with intensities that follow the $J^{\prime}(J^{\prime} + 1)(2J^{\prime} + 1)\exp[- B^{\prime}J^{\prime}(J^{\prime} + 1)/kT]$ formula for rotational coupling with $^{1}\Pi$ states suggested by Wilkinson and Mulliken [1] for the corresponding $a^{\prime}-X$ transition in $N_{2}$. Assignment of lines up to $J^{\prime}=32$ allows for improvement of centrifugal distortion constants for the $O_{2}(c)$ state [2,3], while the measured positions of the low J lines agree with those calculated from known term energies [2-4]. The individual lines in the 9-1 c-b band are as intense as any lines in the Herzberg I (A-X) or Chamberlain $(A^{\prime}-a)$ bands at wavelengths longer than 365 nm. Surprisingly, Herzberg II (c-X) band emissions are much weaker than expected from previous studies of the terrestrial [5,6] and venusian nightglows [7,8]. URI: http://hdl.handle.net/1811/20686 Other Identifiers: 2002-WG-09