Experimental Isotope Shifts in NI II and FE II

This work reports about measurements of isotope structure in Ni II and Fe II. We have used spectra from hollow-cathode lamps that have been recorded with the Fourier Transform Spectrometer at Kitt Peak National Observatory. Measurements of isotope shifts yield useful information about atomic and nuclear properties. With high-resolution spectroscopy at modern telescopes it is also possible to observe isotope shifts in stellar spectra (Leckrone et al. 1991). The importance of a general knowledge about isotope structure for studies of the solar spectrum has recently been pointed out (Kurucz 1992). This is especially true for elements having line-rich spectra and a high solar abundance. Ignoring isotope structure when constructing synthetic spectra may introduce systematic errors in the calculation of line profiles and may therefore affect e.g. abundance determinations.