Atomic data from the IRON Project. XXXIV. Electron impact excitation of Fe XVI

As part of the IRON Project, electron impact excitation eective collision strengths are computed for the ion Fe xvi familiar in solar spectra. A Breit{Pauli R- matrix calculation is performed with a 12-level (n 4) target representation. The calculation for this relatively simple ion is approached as a test case where we can an- alyze in detail most of the eects that contribute to the accuracy of the collision strengths: the energy mesh, rel- ativistic corrections, the asymptotic multipole potentials and contributions from high partial waves. By compar- ing with two recent independent calculations, an accu- racy rating of 10% is assigned to the present eective collision strengths in the electron-temperature range of 10 5 T=K 10 7 .