We report an experimental and theoretical study of the hyperfine structure (hfs) in various metastable states in Nb u. Hyperfine structures of five levels in Nb II have been measured using a combination of the laser-rf double resonance and laser-induced fiuorescence methods in a collinear laserion-beam geometry. Theoretically, for J=2, a multireference calculation of energies and hfs based on a relativistic configuration-interaction methodology of the lowest ten levels in the (4d +5s) manifold is reported.The average energy error is 450 cm '. Many of the hyperfine constants show large changes from the Dirac-Fock values and the magnetic dipole constant has a 4% accuracy for the one J =2 level measured.We have also identified all the core-valence and core-core effects that dominate the energy differences and hfs.PACS number(s): 32.10. Fn, 32.30.Bv, 31.30.Cxs, 31.30.Jv

Our relativistic configuration-interaction (RCI) methodology has been extended to multireference cases, and improved to permit the construction of angular-momentum functions of arbitrary size, and to minimize the number of vectors needed with each configuration. We report RCI calculations on the fine (fs) and hyperfine (hfs) structure for the (d+s) J=0.5 and 1.5 levels of ZrII. The average fs error is 0.075 eV, and 17% for hfs, when compared to available experiment. These results indicate that it is possible to correctly position all levels of (d +s)" configurations in the transition-metal atoms.PACS number(s): 31.30. Gs, 31.20.Tz, 31.30.Jv

No abstract

No abstract