R-Matrix Calculation of Electron Impact Excitation of Fine-Structure Levels of Ne-Like Iron

Abstract

Electronimpact collision strengths for transitions from the ground state to the fine-structure levels of the excited 2p53s, 2p53p, and 2p53d 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 2s22p6(1S), 2s22p53s(1,3Po), 2s22p53p(1,3S, 1,3P, 1,3D), and 2s22p53d(1,3Po, 1,3Do, 1,3Fo) 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.