Experimental oscillator strengths and hyperfine constants in Nb ii
Atomic Astrophysics, Lund Observatory, Box 43, 221 00 Lund, Sweden e-mail: [hampus.nilsson;stefan.ivarsson]@astro.lu.se
Accepted: 14 October 2008
We used high-resolution Fourier transform spectroscopy to measure new and improved transition probabilities and hyperfine data for singly ionized niobium. Intensity calibrated spectra were used to measure branching fractions of 145 Nb ii lines in the wavelength interval 2600–4600 Å. Combining the branching fractions with previously reported lifetimes, absolute oscillator strengths for these 145 transitions were derived. In addition, line structures due to magnetic hyperfine interaction were studied resulting in new hyperfine splitting constants for 28 even and 24 odd energy levels.
Key words: atomic data / methods: laboratory / techniques: spectroscopic / line: identification / line: profiles
© ESO, 2008