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.

The second spectrum of niobium: I. Accurate fine structure study of even-parity levels

“…Later, other palladium group ions were studied successfully with the same goal: Mo II [2], Ru II [3], Pd II [4] and Ag II [5]. Recently, we carried out fine structure (FS) studies of Zr II [6], Hf II [7], Ti II [8] and Ta II [9], enhancing previous works by giving more accurate spin-orbit and Slater integral values and very often for the first time the leading eigenvector percentages of levels and calculated Landé g-factors. Moreover, sometimes we eliminated erroneous levels reported in earlier analyses.…”

Fine, hyperfine and Zeeman structures of levels of 123Sb I

“…Furthermore the accuracy of the amplitude of the energy level eigenvector is known to have particularly a strong influence on the determination of the effective mono-electronic hyperfine structure parameters deduced from magnetic dipole A and electric quadrupole B constants, experimentally obtained. For these reasons we propose to extend previous fs studies, using a method successfully tested for atoms: Si I [31], Hf I [32], Zr I [33], and ions: Nb II [34] Ta II [35], V II [36]. This method should find particular application for systems composed of many Rydberg configurations mutually interacting.…”

“…The last but not the least work was done by Hassini et al [8] who reported 138 levels derived from 617 spectral lines in the range 2536 to 24 786 cm −1 . The method applied here for fine and hyperfine structure studies was successfully used previously as regards neutral and singly ionized atoms: Zr I, Hf I, Nb II, Ta II, V II, Ti II [34][35][36]44,45], gathering the set of their studied configurations in model space when it was possible. In the fs calculations we took into account the basis setup consisted of the 7 interacting configurations: 5s 2 5p 2 6s, The spin-orbit integrals ξ nd and ξ 5p effect the interactions with distant configurations.…”

“…To give it experimental significance we have to weight it by the ratio of spin-orbit constants obtained thanks to fs study and ab initio calculations, i.e. to multiply it by ξ nl (f s)/ξ nl (ab initio) as we did for instance in previous work [35]. Using the expectation values of Table 12 is very satisfactory for two first calculated ratios but rather worse for the last one, maybe because we did not exploit directly some experimental A hfs constants of the 5s5p 4 levels (not available up to now) but only some bits existing in levels of other configurations (see index g in Tab.…”

Fine Structure Analysis of the Configuration System of V II. Part II: Odd-Parity Levels

“…Recently we carried out fs studies of some singly ionised atoms, e.g. Ta II [8] or Nb II [9], in an effort to complete previous works and to eliminate erroneous level assignments. This time we propose a similar work concerning V II, which presents high interest for astrophysical investigations since it is very useful in the study of the history of nucleosynthesis, chemically peculiar stars and the sun.…”