Electron impact excitation of Ar XVII

Department of Physics and Astronomy, Queen's University, Belfast BT7 1NN, Northern Ireland, UK e-mail: K.Aggarwal@qub.ac.uk

Received: 12 May 2005
Accepted: 31 May 2005

Abstract

Energies for the lowest 49 levels among the 1s² and 1s () configurations of Ar XVII have been calculated using the grasp code of Dyall et al. (1989, Comput. Phys. Comm., 55, 424). Additionally, radiative rates, oscillator strengths, and line strengths are calculated for all electric dipole (E1), magnetic dipole (M1), electric quadrupole (E2), and magnetic quadrupole (M2) transitions among these levels. Furthermore, collision strengths have also been calculated for all the 1176 transitions among the above 49 levels using the Dirac Atomic R-matrix Code (DARC) of Norrington & Grant (2005, Comput. Phys. Commun., in preparation), over a wide energy range up to 580 Ryd. Resonances have been resolved in the threshold region, and effective collision strengths have been obtained over a wide temperature range up to log  K. Comparisons are made with the limited results available in the literature, and the accuracy of the data is assessed. Our energy levels are estimated to be accurate to better than 0.1%, whereas results for other parameters are probably accurate to better than 20%.