Analyses of the 5d2–5d7p transitions in the Ta IV and W V spectra

Abstract

The spectra of tantalum and tungsten were photographed on a 3 m normal incidence spectrograph using a sliding spark and a triggered spark light source. The 5d2–5d7p transitions in the Ta IV and W V were investigated. All 12 levels of the 5d7p configuration in both Ta IV and W V have been established. The 5d7p and 5d5f configuration interaction has helped us to identify three of the four missing levels of the 5d5f configuration in Ta IV and one missing level in W V Sixty-six lines in Ta IV and 45 lines in W V have been additionally classified. Parametric calculations interpret the observed spectra satisfactorily. Ionization potentials of Ta IV and WV have been estimated to be Ta V2D3/2 = 294 700 ± 1500 cm−1 (36.53 ± 0.18 eV) and W VI 2D3/2 = 421 300 ± 800 cm−1 (52.22 ± 0.10 eV), respectively.