Isotope shifts and accurate wavelengths in NeII and NeIII

Abstract:
Transition isotope shifts of 3s-3p transitions in Ne II and Ne III are measured in Fourier transform spectra from a hollow-cathode source. Accurate absolute line-center positions of the Ne-20 isotope are derived for the purpose of tertiary wavelength standards in the region 2000-5000 angstrom. A robust statistical treatment is applied, yielding line-position uncertainties that are lower than for the ArII secondary standards used as references. The influence of Stark shifts on both the new NeII standards and the ArII standards is also investigated. In addition, improved wavenumbers of the 3p-3d and 3p-4s transitions are presented, of which 12 in Ne II have been measured for the first time.