Hyperfine structure in 167Er I+II+III: multiconfiguration Dirac-Fock interpretation of measurements

The authors report the first high-resolution measurement of hyperfine structure (HFS) in the 4f12 configuration of 167Er III. Together with recent measurements of HFS in the 4f126s2 configuration of 167Er I and in the 4f126s configuration of 167Er II, these data constitute the first detailed description of HFS along several ionisation stages in a rare-earth element. Based on ab initio, multiconfiguration Dirac-Fock calculations of the magnetic dipole and electric quadrupole coupling constants for experimentally observed levels, several conclusions are drawn in a discussion of the present status of understanding of HFS in typical rare-earth system.