Experimental transition probabilities and improved level energies in YbIII

Radiative lifetimes of nine out of the twelve 4f(13)6p levels in Yb III have been measured, seven of these for the first time. A Penning discharge lamp is introduced as a continuous plasma source, in which the lifetimes are determined with the time-resolved laser-induced fluorescence technique by pumping from metastable 5d and 6s levels. Spectra of the same source are recorded with a Fourier-transform spectrometer, which are used to derive branching fractions of the 6p and 7s levels. Combined with the lifetimes, the branching fractions are used to determine 81 experimental transition probabilities. Wavelengths of 142 Yb III transitions are measured and the uncertainties of corresponding Ritz wavenumbers are improved by an order of magnitude from the prior values. The energy of the 5d (5/2,5/2)(o)(o) level has been shifted 144.20 cm(-1) to the higher value 45421.045 cm(-1). Much emphasis is put on data treatment and error analysis.