Fine structure effective collision strengths for the electron impact excitation of the sulphur ion S V

Abstract

We have performed a 14-state R-matrix calculation to determine effective collision strengths for fine structure transitions in S v ion. The target states were taken to be the 14 lowest LS states, which involve configurations of the form - (2p6)3s2, 3s3p, 3p2, 3s3d, 3s4s, 3p3d. These target states give rise to 26 fine structure levels and 325 possible transitions. The fine structure collision strengths were obtained by transforming to a jj-coupling scheme using the JAJOM program of Saraph and using a sufficiently fine energy mesh so that the resonance structure can be be properly delineated. Effective collision strengths were calculated by averaging the electron collision strengths over a Maxwellian distribution of velocities. Comparisons are made with an earlier R-matrix calculation and with a distorted-wave approximation.