Fast-beam-laser lifetime measurements for energy levels in singly-ionized lutetium and thulium

The radiative lifetimes of four levels in singly ionized lutetium (Lu II) and sixteen levels in singly ionized thulium (Tm II) have been measured using the fast beam-laser technique. The results for the lutetium experiment are in generally fair agreement with the HFR + CP calculation by Quinet et al. Additionally, our results show further evidence of hyperfine structure effects in Lu II. The levels in Tm II were studied in order to resolve disagreement between Anderson et al's experimental results and Quinet et al's theoretical calculations. For fourteen of the the fifteen levels for which there was significant discrepancy between experiment and calculation, our work on Tm II supported the experimental results quoted by Anderson within the quoted errors. In the remaining case, our result is intermediate between the experimental value reported by Anderson et al and the theoretical value reported by Quinet et al.