2009A&A...497..611M

We present a new set of oscillator strengths for 142 FeII lines in the wavelength range 4000-8000Å. Our gf-values are both accurate and precise, because each multiplet was globally normalized using laboratory data (accuracy), while the relative gf-values of individual lines within a given multiplet were obtained from theoretical calculations (precision). Our line list was tested with the Sun and high-resolution (R≃10⁵), high-S/N (≃700-900) Keck+HIRES spectra of the metal-poor stars HD 148816 and HD 140283, for which line-to-line scatter (σ) in the iron abundances from FeII lines as low as 0.03, 0.04, and 0.05dex are found, respectively. For these three stars the standard error in the mean iron abundance from FeII lines is negligible (σ_mean≤0.01dex). The mean solar iron abundance obtained using our gf-values and different model atmospheres is A_Fe=7.45 (σ=0.02).