H. Karlsson et U. Litzen, Revised BaI and BaII wavelengths and energy levels derived by Fourier transform spectroscopy, PHYS SCR, 60(4), 1999, pp. 321-328
Barium spectra emitted from hollow cathode discharges and recorded with Fou
rier transform spectrometers in the region 1700-31 000 Angstrom have been u
sed for measuring 294 Ba I lines and 52 Ba II lines with uncertainties in t
he range +/-0.001 cm(-1) to +/-0.01 cm(-1). Energy level values have been d
erived from the measurements. The energy levels have been used for an impro
ved determination of the Ba II ionization limit, giving the value 80686.30
+/- 0.10 cm(-1).