High-resolution spectroscopy of NaI around the atomic asymptotes Na (3p 2P1/2,3/2)+I ( 2P3/2)

Excitation spectra of NaI were recorded in the wavelength range 239–256 nm with a frequency doubled pulsed dye laser. The assignment of 27 vibrational bands shows that the observed spectra belong to a new bound covalent state below the atomic asymptotes Na(2P1/2,3/2) + I(2P3/2) and above the predissociating state A0+ [S. H. Schaefer, D. Bender, and E. Tiemann, Chem. Phys. 89, 65(1984)]. The Dunham parameters and the potential curve for the new state are given. The potential curve is compared with that derived by the analysis of a fluorescence progression from a broadband excitation that was published recently by Bower et al. [J. Chem. Phys. 89, 4478 (1988)].