The second spectrum of niobium: III. Evaluation of line isotope shifts

Abstract

Using isotope shift values of only one Nb II line, we propose for the first time to predict isotope shifts of all spectral lines for this ion for any pair of isotopes. For this purpose, we had recourse to ab intio calculations to determine specific mass and field shifts of all relevant Nb II configuration averages, which are respectively proportional to the Vinti integral k-factor and the charge density at the nucleus, 4л|Ψ(o)|2. With the help of very accurate level eigenvectors of these configurations and using the sharing rule, we computed specific mass and field shifts of each level. Since a transition wavenumber is the difference between two energy levels, we then deduced line isotope shifts.