Electron collisional excitation of the low-lying fine-structure levels in oxygen-like Fe18+
Abstract
Effective collision strengths for electron impact excitation of all fine-structure levels arising from the 1s22s22p4 ground state configuration of oxygen-like iron ions, Fe18+ (Fe XIX), have been calculated over a range of temperatures applicable to many laboratory and astrophysical plasmas. The R-matrix method, within the semi-relativistic Breit-Pauli approximation, was employed. Twenty fine-structure levels arising from twelve 1s22s22p4, 1s22s2p5, 1s22p6 and 1s22s22p33s LSπ target terms were included in the electron scattering calculation. Comparisons of the present results, which exhibit strong resonance structure in the cross sections, with previous results obtained by distorted wave methods show significant differences.
- Publication:
-
Journal of Physics B Atomic Molecular Physics
- Pub Date:
- November 2001
- DOI:
- 10.1088/0953-4075/34/22/318
- Bibcode:
- 2001JPhB...34.4521M