Transition probabilities for 183 lines of Cr II

The goals of this study are to improve transition probability measurements in Cr II and reconcile solar and stellar Cr abundance values based on Cr I and Cr II lines. Eighteen spectra from three Fourier Transform Spectrometers supplemented with ultraviolet spectra from a high-resolution echelle spectrometer are used in the BF measurements.

Radiative lifetimes from this study and earlier publications are used to convert the BFs into absolute transition probabilities. These new laboratory data are applied to determine the Cr abundance log{epsilon} in the Sun and metal-poor star HD 84937. The mean result in the Sun is <log{epsilon}(CrII)>=5.624+/-0.009 compared to <log{epsilon}(CrI)>=5.644+/-0.006 on a scale with the hydrogen abundance log{epsilon}(H)=12 and with the uncertainty representing only line-to-line scatter.