Full hyperfine structure study of singly ionized tantalum

Abstract

The configuration system of Ta II, both for odd- and even-parities has been considered on the basis of the experimental data available in the literature. The interpretation has been carried out based on a model space for even-parity and refined multiconfigurational fine structure (fs) calculation including the main Rydberg series configurations mutually interacting for odd parity. The sets of fs parameters, the assignments of term designations, as well as the leading eigenvector percentages of levels relevant for this paper are given very often for the first time. The hyperfine structure (hfs) study that follows reveals erroneous experimental data given previously in the literature and some new data are proposed in their place. The single-electron hfs parameters are determined in their entirely for 181Ta II for the lowest configurations with a good accuracy and compared with ab-initio calculations. Finally, a complete list of the predicted hfs constants A and B of all levels of the model space (5d + 6s)4 was generated.