Seventh spectrum of tungsten (W vii); resonance lines of Hf v

Observations of W vii were carried out in the spectral range 100 to 2000 Å utilizing normal- and grazing-incidence spectrographs. The light source was a sliding spark operated at peak currents of 1000 to 3000 A. Eighty-five energy levels of $4f^{13}\mathrm{nl}$ and $5p^5\mathrm{nl}$ configurations were deduced for $nl=5d, 6s, 6p, 6d, \mathrm{and} 7s$. These are based on the classification of 310 lines in the range 130 to 1436 Å. Calculations of all observed configurations were carried out with configuration interaction (CI) for the purpose of fitting radial integrals and confirming the analysis. The strong CI between $p^5\mathrm{nl}$ and $f^{13}\mathrm{nl}$ configurations where $nl=5d, 6p, 6d$ provided well-defined CI integrals in good agreement with Hartree-Fock values. A value of 984 100 ± 500 ${\mathrm{cm}}^{-1\mathrm{}}$ was derived for the ionization energy from the $4f^{13}\mathrm{ns}$ series. The resonance lines of Hf v for $5p^6-5\mathrm{}{p}^{5}5d$, $6s$ are given. A revised value for the the ionization energy of W vi is given.