Radiative lifetimes of 6 levels belonging to the4f<SUP>5</SUP>(<SUP>6</SUP>H<SUP>deg</SUP>,<SUP>6</SUP>F<SUP>deg</SUP>)5d configuration of Sm III have beenmeasured for the first time using a time-resolved laser-inducedfluorescence technique. Experimental data have been compared withsemi-empirical calculations. The agreement is excellent for 4 levelswith <SUP>6</SUP>F<SUP>deg</SUP> as a parent term. Larger discrepancies(53 and 37) are observed for 2 levels with <SUP>6</SUP>H<SUP>deg</SUP>and <SUP>6</SUP>F<SUP>deg</SUP>, respectively, as a parent term and areexplainable by strong mixing and cancellation effects occurring in theline strength calculations which are responsible of instabilitiesoccurring in the lifetimes considered as a function of J value withinthe term. Branching ratios for the lines depopulating the levels ofinterest have been measured by Fourier transform spectroscopy. A firstset of oscillator strengths has been deduced for this ion.
- Astronomy, Astrophysics and Cosmology
- Atom and Molecular Physics and Optics
- atomic processes
- atomic data
- stars: chemically peculiar