Revised and extended analysis of the fourth spectrum of indium: In IV

The spectrum of triply ionized indium (In IV) has been investigated in the wavelength region 245-4443 angstrom. The In3+ is a Pd-like ion with the ground configuration 4p(6)4d(10). All levels of the low lying excited configurations 4d(9)5p, 4d(9)ns (n=5-7), 4d(9)5d and 4d(8)5s(2) have been reported earlier, while for the higher configurations 4d(9)np (n=6,7) and 4d(9)nf (n=4-11), only the J=1 levels radiatively decaying to the ground level have been reported. The present work extends the analysis to include the 4d(9)6p, 4d(9)6d, 4d(9)4f and 4d(9)5f configurations. A total 116 levels have been established, 56 of them being new. All the previously reported levels have been confirmed except 4d(9)7s D-3(1), 4d(9)7p P-3(1), 4d(9)6f P-3(1) and 4d(8)5s(2) P-3(1). The experimental data for the present work was recorded on a 3-m normal incidence spectrograph of St. Francis Xavier University, Antigonish (Canada), as well as on the 10.7 m normal and grazing incidence spectrographs of the National institute of Standards and Technology, Gaithersburg (USA). In both laboratories, a triggered spark source was used. The wavelengths above 2000 angstrom were supplemented from Bhatia's thesis where an electrodeless discharge source was used. Theoretical predictions were made using Cowan's Hartree-Fock-relativstic atomic codes with superposition of configurations. Least squares fitted (LSF) parametric calculations were used to interpret the energy levels. For vacuum ultraviolet wavelength region our wavelength accuracy is +/- 0.005 angstrom. We estimate the ionization potential of In IV to be 450,921.7 +/- 86.0 cm(-1) (55.9072 +/- 0.0106 eV). (C) 2013 Elsevier Ltd. All rights reserved.