Isotope shifts in the arc spectra of dysprosium, erbium, and ytterbium*

Abstract

Atomic isotope shifts in the spectra of dysprosium, erbium, and ytterbium have been measured using enriched samples and a Fabry-Perot interferometer. Results include new data on 5 lines in Dy i, on 71 lines in Er i, and for 89 lines in Yb i. Correlation of electron configurations indicates that for these elements fn6s7s–fn6s6p transitions show an average isotope shift of +28 mK, fn−15d6s6p–fn−15d6s2 exhibit shifts of −86 mK, fn5d6s–fn−15d6s2 lines have shifts of −105 mK, fn−15d26s–fn6s2 show shifts of −20 mK, while fn6s6d–fn6s6p and fn−16p6s2–fn−15d6s2 transitions exhibit no detectable shifts. Using these isotope shift trends, 17 levels of Yb i have been identified as belonging to 4f13 5d6s6p configurations.