Vacuum ultraviolet resonance absorption f-values for NiII

We have used the High Sensitivity Absorption Spectroscopy experiment at the Synchrotron Radiation Center in Stoughton, Wisconsin, to measure relative absorption oscillator strengths, or f-values, for six resonance transitions of Ni+ in the vacuum ultraviolet. This laboratory absorption work is an ex tension of recent laser induced fluorescence and emission work which establ ished an accurate, absolute scale for Ni II resonance f-values. The relativ e absorption f-values are normalized using three absolute f-values for Ni I I, previously determined by combining experimental radiative lifetimes and emission branching fractions, to produce an expanded set of seven absolute resonance f-values for Ni II. Accurate f-values for Ni II resonance lines a re critical to the analysis of spectra on the diffuse interstellar medium a nd are used to determine various properties of the ISM. Resonance lines of Ni II are also observed in high redshift QSO absorption line systems.