Radiative lifetime measurements and transition probability calculations in lanthanide ions

Abstract

We have undertaken a systematic investigation of spectroscopic properties of lanthanide ions ( Z=57–71). Using time-resolved laser-induced fluorescence following one- or two-photon excitations, a large number of radiative lifetimes have been measured at the Lund Laser Centre for singly, doubly and trebly ionized atoms. These new measurements have been used for testing theoretical calculations performed within the framework of a relativistic Hartree–Fock approach taking core-polarization effects into account. Using the experimental lifetimes (when available) and the theoretical branching fractions, a large number of transition probabilities, most of them of astrophysical interest, have been deduced and are stored in a new database (DREAM). Up to now, the results obtained concern the following ions: La 2+, Ce +, Ce 3+, Pr 2+, Ho 2+, Er 2+, Tm +, Tm 2+, Yb +, Yb 2+, Yb 3+, Lu + and Lu 2+.