Lifetimes and hyperfine structures in Ho II

In this work we have measured lifetimes, oscillator strengths and hyperfine structures in Ho II. Accurate atomic structure data are of importance for element identification in stellar atmospheres as well as in atomic structure studies. Lifetimes of 3 excited levels, all observed in stellar spectra, have been measured using electro-optic modulation spectroscopy in the ultraviolet. Oscillator strengths have furthermore been extracted by analyzing the time evolution of the laser excitation in the Rabi-regime. Previous to this study no lifetime and oscillator strength data were known in Ho II. In addition, the hyperfine structures of 3 low odd levels and 2 excited levels, has been accurately measured using fast beam laser spectroscopy. These data are analyzed using Multi-Configuration Dirac-Fock (MCDF) wavefunctions. (orig.)