Analysis of the 4p⁶4d⁸4f and 4p⁵4d¹⁰Configurations of Xe X and Some Highly Excited Levels of Xe VIII and Xe IX Ions

The spectra of various ions of xenon were investigated in the 70–170 Å region. The earlier analysis of the 4d 9 –4d 8 5p transitions Kaufman et al. , J. Opt. Soc. Am. B 73 , 691 (1983) in Rh-like Xe X was confirmed except for the two highest 4d 8 ( 1 S)5p 2 P levels. The 4p 6 4d 9 –(4p 6 4d 8 5p 8 4f +4p 5 4d 10 ) transitions arrays were studied. We have established 28 new levels belonging to the odd parity system and classified 40 additional lines in Xe X. The spectrum is adequately described by the Hartree–Fock and parametric least-squares-fitting calculations. The resonance transitions from the highly excited 4d 9 (6p+5f+7p+6f) levels in Pd-like Xe IX and the 4 10 5s 2 S–4d 9 5s4f 2 P transitions in Ag-like Xe VIII have also been identified. The ionization potential of Xe IX has been calculated to be 1450500±1000 cm -1 (179.85±0.10 eV). The results from all three spectra are in good agreement with the Rh I, Pd I and Ag I isoelectronic sequences data.