Investigation of the Hyperfine Structure of Ta I Lines (VII)

New levels of Ta II with energies higher than 72,000 cm −1

“…In a photographic spectrum, taken by a grating spectrograph in high order, the emission spectra of an Ar-Ta hollow cathode discharge were compared for different working conditions. One spectrum was taken operating the discharge with dc current, and another one operated with a pulsed current [10]. We found out that in the pulsed discharge the ionic lines were more intense, allowing us to identify 3235.130 Å as an ionic line.…”

“…The FT spectra available to us were recorded at the Imperial College London and the Kitt Peak observatory and cover the range from 2120 Å up to 47,000 Å [9,10]. The resolution of the FT spectra were chosen between 0.03 and 0.05 cm À 1 in order to obtain high sensitivity and to resolve the Doppler width of the lines as good as possible.…”

“…Zilio and Pickering analyzed a FT spectrum and could give a number of hf constants for levels, for which these numbers were not known before [9]. Later on, improved FT spectra from the Kitt Peak observatory and the spectra of the group of J.C. Pickering at Imperial College became available to our group in Graz and did lead to a remarkable improvement of our investigations concerning Ta I and Ta II [10]. The first results on Ta II were reported already in Refs.…”