Line strengths for E2 transitions in Fe XVI

The relativistic quantum defect orbital (RQDO) formalism is applied to elec tric quadrupole (E2) transitions for the first time. The RQDO calculations have been performed in the LSJ-coupling scheme on E2 transitions between le vels belonging to several astrophysically important configurations of Fe XV I. A number of line strengths are reported and compared with those found in the literature. A good agreement with the comparative data as well as the expected systematic behaviour of the RQDO line strengths along the spectral series confirms earlier conclusions about the quality of the RQDO wavefunc tions.