OSCILLATOR-STRENGTHS FOR FE-II TRANSITIONS AT 224.918 AND 226.008 NANOMETERS

We report accurate experimental absorption oscillator strengths (f-values) for transitions out of the ground level of Fe II to the z(4)D(7/2)(0) and z(4)F(9/2)(0) levels at 224.918 and 226.008 nm (air wavelengths) to be 0.00182(14) and 0.00244(19), respectively. The number in parenthesis is the uncertainty in the last digits. These two lines are important for studying Fe abundances and grain depletions in the interstellar medium. These f-values are determined by combining emission branching fractions with radiative lifetimes. Branching fractions are measured using classical spectroradiometry on an optically thin source. Radiative lifetimes are from the literature.