Electron impact excitation of Mg-like iron

Collision strengths for transitions among the energetically lowest 53 fine-structure levels belonging to the (1s 2 2s 2 2p 6 )3 2 , 3 3 ´, 3s4 and 3p4 configurations of Fe XV are computed, over an electron energy range of 20 E 160 Ryd, using the recent Dirac atomic R -matrix code (DARC) of Norrington and Grant. All partial waves with J 39.5 have been included, and a contribution of higher partial waves has been added to ensure the convergence of collision strengths for all transitions and at all energies. The results are compared with those available in the literature, and the accuracy of the data is assessed.