IMPROVED log( gf ) VALUES OF SELECTED LINES IN Mn I AND Mn II FOR ABUNDANCE DETERMINATIONS IN FGK DWARFS AND GIANTS

The goal of the present work is to produce transition probabilities with very low uncertainties for a selected set of multiplets of Mn i and Mn ii. Multiplets are chosen based upon their suitability for stellar abundance analysis. We report on new radiative lifetime measurements for 22 levels of Mn i from the e8D, z6P, z6D, z4F, e8S, and e6S terms and six levels of Mn ii from the z5P and z7P terms using time-resolved laser-induced fluorescence on a slow atom/ion beam. New branching fractions for transitions from these levels, measured using a Fourier-transform spectrometer, are reported. When combined, these measurements yield transition probabilities for 47 transitions of Mn i and 15 transitions of Mn ii. Comparisons are made to data from the literature and to Russell–Saunders (LS) theory. In keeping with the goal of producing a set of transition probabilities with the highest possible accuracy and precision, we recommend a weighted mean result incorporating our measurements on Mn i and ii as well as independent measurements or calculations that we view as reliable and of a quality similar to ours. In a forthcoming paper, these Mn i/ii transition probability data will be utilized to derive the Mn abundance in stars with spectra from both space-based and ground-based facilities over a 4000 Å wavelength range. With the employment of a local thermodynamic equilibrium line transfer code, the Mn i/ii ionization balance will be determined for stars of