: |
: |
|---|
g
X3
-g BAND OF OXYGEN NEAR 1.27 µm: MAGNETIC DIPOLE AND ELECTRIC QUADRUPOLE TRANSITIONS IN SPECTRA OF FIVE ISOTOPOLOGUES.
O. M. LESHCHISHINA, S. KASSI, L. WANG, Université Joseph Fourier/CNRS, Laboratoire de Spectrométrie Physique, 38402 Saint Martin d'Hères, FRANCE; I. E. GORDON, L. S. ROTHMAN, Harvard-Smithsonian Center for Astrophysics, Atomic and Molecular Physics Division, Cambridge MA 02138-1516, USA; A. CAMPARGUE, Université Joseph Fourier/CNRS, Laboratoire de Spectrométrie Physique, 38402 Saint Martin d'Hères, FRANCE.
The knowledge of accurate spectroscopic parameters for the a1
g
X3
-g band of molecular oxygen near 1.27 µm is very important in the field of remote sensing. Although this band was studied by spectroscopists for over a century a lot of discrepancies still remain in the previously reported line positions and intensities. In this work the Continuous Wave-Cavity Ring Down Spectroscopy (CW-CRDS) technique has been used to record with high sensitivity the absorption spectrum of this band. The spectra were obtained between 7640 and 7917 cm-1 with ``natural'' oxygen and with a sample highly enriched in 18O. The absolute intensities of 377 and 652 oxygen transitions were measured in the two spectra, respectively. They include the a1
g
X3
-g (0-0) bands of 16O2, 16O18O, 16O17O, 17O18O and 18O2. The (0-0) bands of 16O2 and 18O2 show (previously undetected) electric quadrupole transitions with line intensities ranging from 1×10-30 to 1.9×10-28 cm/molecule. They are accompanied by the a1
g
X3
-g (1-1) hot bands which are also reported for the first time. Accurate spectroscopic parameters for the observed bands were derived from a global fit of the experimental line positions, combined with microwave and Raman measurements available in the literature.