Radiative lifetime and oscillator strength determinations in Sm III

Radiative lifetimes of 6 levels belonging to the4f5(6Hdeg,6Fdeg)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 6Fdeg as a parent term. Larger discrepancies(53 and 37) are observed for 2 levels with 6Hdegand 6Fdeg, 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