Electron impact excitation of FeII: Total LS effective collision strengths

We present total effective collision strengths for electron-impact excitation of Fe II, calculated using the parallel R-matrix program PRMAT, for all sextet to quartet forbidden transitions among the lowest 113 LS states formed from the 3d(6)4s, 3d(7), 3d(5)4s(2), 3d(6)4p and 3d(5)4s4p basis configurations. After a detailed and systematic study of configuration-interaction effects in both the target and the collision wavefunctions, it was found that an additional 21 configurations needed to be included in the CI expansion to obtain significantly more accurate target state and collision wavefunctions. A total of 1785 individual lines are considered over a wide range of electron temperatures, 30-100000 K, of particular importance in astrophysical applications. A detailed comparison is made with a previous 3 configuration approximation and significant differences of up to a factor of 2 are reported at the lowest temperatures considered. The inclusion of the additional 3d(5)4s(2) and 3d(5)4s4p levels in the present work together with the additional Cl effects are found to cause significant changes to the total effective collision strengths for the low-lying transitions from the ground state, particularly at very low temperatures. The disparities are found to be considerably less at the higher temperatures considered.