Additions to the Analysis of Vanadium V

The spectrum of four-times-ionized vanadium has been observed by using a 5-m grazing-incidence and a 3-m normal-incidence spectrograph. The light sources have been a vacuum sliding spark and an open vacuum spark. This paper presents some additions to the analysis by C. H. H. Van Deurzen. 42 lines have been classified as ground-term transitions and 6 lines as combinations between excited terms. These transitions have established the levels of the nf -series up to 9 f as well as 10 levels of 3 p 5 3 d 2 and 4 levels of 3 p 5 3 d 4 s . By applying the polarization formula to the hydrogen-like terms 5 g , 6 g , 7 g , 6 h , 7 h and 7 i as given by Van Deurzen the ionization energy has been determined to 526 530±4 cm -1 (65.280 eV).