Progress in the analysis of the even parity configurations of tantalum atom

The experimental work of L. Windholz, G.H. Guthöhrlein and co-workers, concerning observation of the tantalum spectrum, yield many information about new energy levels and hyperfine structure splitting. We contribute the results of the complex parametric studies of the fine- and hyperfine structure of the mentioned element up to second-order of perturbation theory, including the effects of closed shell - open shell excitations. The work has been performed for the systems including 47 even configurations. The values of the radial parameters describing the one- and many-body interactions effects on atomic structure are given. We predicted values of energy levels and their A- and B- hyperfine structure constants, also for experimentally levels not observed up to now

Parametric study of the fine and hyperfine structure for the even parity configurations of atomic niobium

In this work a parametric study of the fine and hyperfine structure (hfs) for the even parity configurations of atomic niobium (Nb I) is presented. A large amount of new experimental data, published during the last decade, have been considered for the fine and hfs analysis. A multi-configuration fit of 14 configurations have been performed by taking into account second-order of perturbation theory including the effects of closed shell-open shell excitations. Predicted values of level energies as well as magnetic dipole and electric quadrupole hfs constants of A and B are listed, if no experimental values are available