Critically Evaluated Energy Levels, Spectral Lines, Transition Probabilities, and Intensities of Singly Ionized Vanadium (V ii)

The energy levels, observed spectral lines, and transition probabilities of singly ionized vanadium, V ii, have been compiled. The experimentally derived energy levels belong to the configurations 3 d ⁴, 3 d ³ ns ( n  = 4, 5, 6), 3 d ³ np , and 3 d ³ nd ( n  = 4, 5), 3 d ³4 f , 3 d ²4 s ², and 3 d ²4 s 4 p . Also included are values for some forbidden lines that may be of interest to the astrophysical community. Experimental Landé g -factors and leading percentages for the levels are included when available, as well as Ritz wavelengths calculated from the energy levels. Wavelengths and transition probabilities are reported for 3568 and 1896 transitions, respectively. From the list of observed wavelengths, 407 energy levels are determined. The observed intensities, normalized to a common scale, are provided. From the newly optimized energy levels, a revised value for the ionization energy is derived, 118,030(60) cm⁻¹, corresponding to 14.634(7) eV. This is 130 cm⁻¹ higher than the previously recommended value from Iglesias et al.