$O_{2}(c^{1}\sum^{-}_{u}-b^{1}\sum^{+}_{g})$ BAND EMISSION IN THE TERRESTRIAL NIGHTGLOW
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Date
2002
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Ohio State University
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].
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[1] P. G. Wilkinson and R. S. Mulliken, J. Chem. Phys. 31, 674 (1959). [2] D. A. Ramsay, Can. J. Phys. 64, 171 (1986). [3] K. Yoshino, J. R. Esmond, W. H. Parkinson, A. P. Thorne, R.C.M. Learner, and G. Cox, J. Chem. Phys. 111, 2960 (1999). [4] H. D. Babcock and L. Herzberg, Astrophys. J. 108, 167 (1948). [5] T. G. Slanger and D. L. Huestis, J. Geophys. Res. 86, 3551 (1981); 88, 4137 (1983). [6] J. Stegman and D. P. Murtach, Planet. Space Sci. 36, 927 (1988). [7] V. A. Krasnopolsky, A. A. Krysko, V. N. Rogachev, and V. A. Parshev, Cosmic Res. 13, 687 (1977). [8] T. G. Slanger, P. C. Cosby, D. L. Huestis, and T. A. Bida, Science 291, 463 (2001).
Author Institution: Molecular Physics Laboratory
Author Institution: Molecular Physics Laboratory