Lifetime and transition probability determination in Xe IX

A new set of transition probabilities is proposed for Xe IX. They have been calculated by two different theoretical approaches i.e. a fully relativistic multiconfiguration Dirac-Fock (MCDF) method and a partly relativistic Hartree-Fock (HFR) approach taking core-polarization effects into account. Their accuracy has been evaluated through comparisons with lifetime measurements for 11 levels performed using beams of Xe+ ions produced by a 2 MV Van de Graaff accelerator. The agreement theory-experiment is nice for most of the levels and gives more weight to the theoretical models used for the calculations and, consequently, to the new transition probabilities.