LASER-INDUCED RESONANCE FLUORESCENCE SPECTROSCOPY.

Author Institution: Joint Institute for Laboratory Astrophysics; National Bureau of StandardsThe argon ion laser lines at 4658, 4727, 4880, 4965, 5017 and $5145\AA$ are each found to excite one or more resonance fluorescence series of the $Na_{2} (X {^{1}}\Sigma_{g}^{+} - B {^{1}} II_{u})$ blue-green band system. Altogether, nineteen different fluorescence progressions have been identified and assigned v,J quantum numbers. The absolute wavenumbers of many of these emission lines have been measured interferometrically using a Fabry-Perot etalon crossed with a Bass-Kessler type spectrograph. A revised set of spectroscopic constants has been determined for both the upper and lower states which reproduce the observed term energies to better than $0.1 cm^{-1}$ on the average. Using these improved spectroscopic data, potential curves have been constructed for the B and X states of $Na_{2}$ by the Rydberg-Klein-Rees method. These potential curves are used in turn to compute Franck-Condon factors for the $Na_{2}$ B-X band system