Fine structure effective collision strengths for the electron impact excitation of Al III

• Published in: Astronomy and astrophysics (Berlin) Vol. 436; no. 3; pp. 1131 - 1139
• Main Authors: Hudson, C. E., Bell, K. L.
• Format: Journal Article
• Language: English
• Published: Les Ulis EDP Sciences 04.06.2005
• Subjects: atomic processes; line: formation; methods: analytical; Electron impact excitation; Atomic process; Line formation; atomic processes; Electron collisions; Velocity distribution; Configuration interaction; Fine structure; Electron temperature; line: formation; Analytical method; methods: analytical; Wave functions; R matrix; Resonance; Maxwell distribution
• ISSN: 0004-6361; 1432-0746
• DOI: 10.1051/0004-6361:20042251

A 10-state R-matrix calculation has been carried out to generate fine structure effective collision strengths for the electron impact excitation of doubly ionized aluminium. The target states are represented by configuration interaction wavefunctions and consist of the 10 lowest LS states – (2p6)3s, 3p, ..., 5p, 5d. These 10 target states give rise to 17 fine structure levels and 136 possible transitions. The fine structure collision strengths were obtained by transforming to a jj-coupling scheme using the JAJOM program of Saraph and have been determined at a sufficiently fine energy mesh to delineate properly the resonance structure. The effective collision strengths were calculated by averaging the electron collision strengths over a Maxwellian distribution of velocities. Tabulations of the non-zero effective collision strengths for transitions between both the LS states and the fine structure levels are given for electron temperatures (Te) in the range $\log_{10} T_{\rm e} ({\rm K}) = 3.6{-}5.6$. Comparisons are made with previous calculations and we find good agreement with the work of Kimura et al. (1998).