Measurements and Calculations of Radiative Parameters for Odd-parity Levels in Nb ii

Experimental radiative lifetimes for 34 odd-parity levels belonging to 4d (3)5p and 4d (2)5s5s configurations of Nb ii were measured by the time-resolved laser-induced fluorescence method. The results range from 2.2 to 11.5 ns, and 30 of them were reported for the first time, as far as we know. The theoretical radiative lifetimes for these levels were also calculated by the pseudorelativistic Hartree-Fock method including core-polarization contributions (HFR+CPOL) and the fully relativistic multiconfiguration Dirac-Hartree-Fock method, and branching fractions for these levels were also calculated by HFR+CPOL. By combining the experimental lifetimes and the calculated branching fraction values, the semiempirical transition probabilities and oscillator strengths for 389 Nb ii lines were obtained.