4f135s25p6-4f135s25p56s transitions in the W VIII spectrum and spectra of isoelectronic hafnium, tantalum, and rhenium ions

Spectra of hafnium, tantalum, tungsten, and rhenium in the range of 145–350A, excited in a low-inductive vacuum spark, have been recorded on a grazing-incidence vacuum spectrograph using a grating with 3600 lines/mm and a radius of 3 m. The wavelengths and intensities of more than 3800 lines in the tungsten spectrum have been measured. Comparison with the Hartree-Fock calculations showed that most spectral lines should be due to transitions in the W VIII spectrum. Short-wavelength lines due to the 4f 135s 25p 6-4f 135s 25p 56s transitions have been identified in the W VIII spectrum and the Re IX, Ta VII, and Hf VI isoelectronic spectra.