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.