R-matrix calculation of electron impact excitation of fine-structure levels of Ne-like iron

Electron impact collision strengths for transitions from the ground state to the fine-structure levels of the excited 2p(5)3s, 2p(5)3p, and 2p(5)3d configurations in Fe XVII are calculated using a Breit-Pauli R-matrix method. The results are presented at 70 and 200 Ry. We considered the lowest 15 LS 2s(2)2p(6)(S-1), 2s(2)2p(5)3s(P-1,3(o)), 2s(2)2p(5)3p(S-1,S-3, (1,3)p, D-1,D-3), and 2s(2)2p(5)3d(P-1,3(o), D-1,3(o), F-1,3(o)) states of Fe XVII in the present calculation. The 15 LS states give rise to 27 fine-structure levels which are represented by configuration-interaction wave functions. The relativistic effects are incorporated in the Breit-Pauli approximation by including one-body mass correction, Darwin, and spin-orbit interaction terms in the scattering equations. Our collision strengths are compared with those from other calculations. The excitation cross sections are integrated over a Maxwellian distribution of electron energies to give electron excitation rate coefficients over a wide temperature range from 250 to 1000 eV. The relative populations for different electron densities and temperatures are also presented. (C) 2000 Academic Press.