Improved Laboratory Transition Probabilities for Pt<scp>i</scp>and Application to the Platinum Abundances of BD +17o3248 and the Sun

Abstract

Radiative lifetimes, accurate to ±5%, have been measured for 58 odd-parity levels of Pt I using laser-induced fluorescence. The lifetimes were combined with branching fractions measured using grating and Fourier transform spectrometry to determine transition probabilities for 127 lines of Pt I. The new Pt lifetime measurements were found to be in good agreement with previous but less extensive measurements based on laser-induced fluorescence. The new branching fraction measurements were found to be in fair agreement with one earlier study. Absolute atomic transition probabilities from the new measurements were used to determine the platinum abundance in the metal-poor Galactic halo star BD +17°3248. An attempt to refine the solar photospheric abundance of platinum was unsuccessful; the single Pt I line used in an earlier abundance determination was found to be even more severely blended than expected from earlier work.