Dirac R-matrix collision strengths and effective collision strengths for transitions of Ni xvii

Abstract

Context. Electron impact excitation collision strengths are required for the analysis and interpretation of stellar observations. Aims. This calculation aims to provide fine structure effective collision strengths for the Nixvii ion using a method which includes contributions from resonances. Methods. A fully relativistic R-matrix calculation has been performed using the DARC code. In the structure part of our calculation 141 fine-structure levels are employed and 37 of these are used in the scattering calculation. Results. Collision strengths have been determined for 666 fine-structure transitions arising from the 37 lowest j-levels involving configurations 3s 2 ,3 p 2 ,3 d 2 , 3s3p, 3s3d, 3p3d and 3s4s. The effective collision strengths for these transitions have been calculated for electron temperatures (Te) in the range log 10 Te(K) = 4.5−8.0. Effective collision strengths are tabulated for transitions between the first ten fine structure levels, arising from the 3s 2 , 3s3p and 3p 2 configurations. The remaining transitions are available at the CDS as