Spectra of the W VIII isoelectronic sequence: III. Re IX

Abstract

Rhenium spectra excited in vacuum spark sources of different setups and electric circuits were recorded on two high resolution vacuum spectrographs: a 10 m normal incidence spectrograph with a 3600 l mm−1 grating in the Meudon Observatory and a 3 m grazing incidence spectrograph with a 3600 l mm−1 grating in the Institute of Spectroscopy in Troitsk. A total of 112 lines in the region 146–244 Å were identified as transitions from the interacting excited even configurations 4f125s25p65d + 4f135s25p5(5d + 6s) + 4f145s25p4(5d + 6s) to the low-lying odd configurations 4f135s25p6 and 4f145s25p5. A change of the ground configuration from 4f135s25p6 to 4f145s25p5 in a comparison with the previous spectra of the isoelectronic sequence Hf VI–W VIII was observed. Fine structure splittings and relative positions of the odd terms were established, and 83 levels of the excited even configurations were found.