title: Influence of resonances on spectral formation of x-ray lines in Fe XVII.
abstract: New theoretical results from large-scale relativistic close coupling calculations reveal the precise effect of resonances in collisional excitation of x-ray lines of Ne-like Fe XVII. By employing the Breit-Pauli R-matrix method and an 89-level eigenfunction expansion, including up to n = 4 levels, significant resonance enhancement of the collision strengths of forbidden and intercombination transitions is shown. The present results should help resolve long-standing discrepancies; in particular, the present line ratios of three benchmark diagnostic lines 3C, 3D, and 3E at 15.014, 15.265, and 15.456 A, respectively, are in excellent agreement with two independent measurements on electron-beam ion traps. Strong energy dependence in cross sections due to resonances is demonstrated.
authors.affiliation: Department of Astronomy, The Ohio State University, Columbus, Ohio 43210, USA.
authors.forename: Guo Xin
authors.initials: GX
authors.lastname: Chen
authors.forename: Anil K
authors.initials: AK
authors.lastname: Pradhan