Analysis of the 4d^9–4d^85p transitions in eleven-times ionized barium (Ba xii)

The spectrum of eleven-times ionized barium was generated in a triggered, high-voltage, vacuum spark and photographed with the National Bureau of Standards 10.7-m grazing-incidence spectrograph. The spectral lines of the transition array 4d9–4d85p were identified in the range of 100–125 A. Thirty-nine lines of this array have been classified as transitions from thirty-two levels of the 4d85p configuration to the 4d9 2D ground term. Radial energy integrals were fitted to the observed levels of 4d85p, and the relative intensities in the array were calculated with fitted eigenvectors. These intensities were in good qualitative agreement with the relative intensities that had been visually estimated on the photographic plate. Least-squares-fitted values for the energy parameters and their ratios to the calculated Hartree–Fock (HF) values are given.