Polarization of Fe XXV 1s2-1s2l lines : collisional resonances and radiative cascade contributions to 1s2l magnetic-sublevel excitation rates

The effects of collisional resonances and radiative cascades on the linear polarization of He-like iron (Fe XXV) lines from 1s2l to 1s 2 levels have been investigated. Detailed calculations have been carried out for the 1s3l3l' resonance contributions to electron-impact excitation rates from the 1s 2 ground level to the individual magnetic sublevels of 1s2l configurations. Excitation collision strengths from 1s 2 to 1s3l sublevels as well as radiative cascade transitions from 1s3l to 1s2l' sublevels have also been computed