Revision and Extension to the Analysis of the Third Spectrum of Tellurium: Te III

The spectrum of doubly ionized tellurium atom (Te III) has been investigated in the vacuum ultraviolet-wavelength region. The ground configuration of Te III is 5s(2)5p(2) and the excited configurations are of the type 5s(2)5p nl. The core excitation leads to a 5s5p(3) configuration. Cowan's multi-configuration interaction code was utilized to predict the ion structure. The observed spectrum of tellurium was recorded on a 3-m normal incidence vacuum spectrograph of Antigonish Laboratory (Canada) in the wavelength region of 300 - 2000 angstrom by using a triggered spark light source for the excitation of the spectrum. The 5s(2)5p(2) - [5s(2)5p (5d + 6d + 7d + 6s + 7s + 8s) + 5s5p(3)] transition array has been analyzed. Previously reported levels by Joshi et al have been confirmed while the older analysis by Crooker and Joshi has been revised and extended to include the 5s(2)5p (5d, 6d, 7d, 6s,7s, 8s) and 5s5p(3) configurations. Least-squares- fitted parametric calculations were used to interpret the final results. One hundred and fifty spectral lines have been identified to establish 60 energy levels. Our wavelength accuracy for unblended and sharp lines is better than +/- 0.005 angstrom. The ionization potential of Te III was found to be 224550 +/- 300 cm(-1) (27.841 +/- 0.037eV).