Ab initio lifetimes, Landé g-values and hyperfine structure for Ta II states

Ab initio Dirac-Coulomb (Breit) configuration-interaction calculations have been done for the lowest four (8, 12) J = 0 (J = 1,2) (5d + 6s)⁴ states and the lowest 12 (5d + 6s)³6p J = 1 states of Ta II. Nearly 20 000 basis functions were used for each state. Energy differences, magnetic dipole hyperfine constants and Landé g-values were calculated, and are in good agreement with available experiment. Lifetimes and branching ratios were calculated for the odd-parity levels, and agree well with experiment, except in one case.