Improved log(GF) values of selected lines in Mn I and Mn II for abundance determinations in FGK dwarfs and giants

摘要

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 e ~8 D, z ~6 P, z ~6 D, z ~4 F, e ~8 S, and e ~6 S terms and six levels of Mn II from the z ~5 P and z ~7 P 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 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 different evolutionary states.