Measurement of Transition Probabilities for Mn I Lines and the Manganese Solar Abundance

Absolute transition probabilities have been measured for 81 lines from 14 upper levels of Mn I. Upper limits of transition probabilities for another 14 lines from 7 of these levels have also been measured. The method used was the measurement of relative transition probabilities (branching ratios) of lines from each upper level and the normalization of these relative probabilities to a scale set by the measured lifetime of the upper level. The lifetimes were measured by the technique of beam-foil spectroscopy. The transition probabilities of four lines were used with equivalent widths measured from the Preliminary Edition of the Kitt Peak Solar Atlas (Brault and Testermann 1972) and the model atmosphere of Goldberg et al. (1960) to calculate a value for the solar abundance of manganese of AMn = 5.44 ± .10. The ratios of abundances of manganese, iron and nickel, values for the latter two elements taken from the table of Ross and Aller (1976), were compared with corresponding ratios predicted by four models of nucleosynthesis. The closest agreement with the observations was obtained from models using combinations of explosive oxygen burning, explosive silicon burning and the e process with α-rich freeze-out.