High-sensitivity absorption spectroscopy in Fe II

We report the first measurements of UV oscillator strengths (f-values) in Fe II from a high-sensitivity absorption experiment developed at the University of Wisconsin. The accuracy of our measurements is demonstrated by our reproducing well-known f-value ratios in Fe I and Fe II. The first laboratory f-value measurement of the 160.845 nm transition in Fe II is presented and compared to values in the literature. While this paper focuses on Fe II, the high-sensitivity absorption method that we have developed is applicable to essentially every element in the periodic table, for both neutral and singly ionized species, over a broad range of wavelength and line strength.