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 Ni xvii 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 , 3p 2 , 3d 2 , 3s3p, 3s3d, 3p3d and 3s4s. The effective collision strengths for these transitions have been calculated for electron temperatures (T e ) in the range log 10 T e (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 well as via the author's website.

R-matrix electron-impact excitation data for the Mg-like iso-electronic sequence

“…Electron-impact excitation data for Ni 16+ have been calculated by Bhatia & Landi (2011), using the FAC distorted wave code, from the lowest 4 levels up to the 159 levels of their target expansion, and by Hudson et al (2009Hudson et al ( , 2012 using the Dirac R-matrix suite of codes on including 37 close-coupling levels.…”

Division B Commission 14 Working Group: Collision Processes

“…For Be-like ions data has been presented for ions from B + to Zn 26+ (Fernández-Menchero et al 2014a), and also Cl 13+ , K 15+ and Ge 28+ (Aggarwal & Keenan 2014d) and Ti 18+ (Aggarwal & Keenan 2012f). For B-like ions data covering from C + to Kr 31+ (Liang et al 2012), and also Al 9+ (Aggarwal & Keenan 2014a) (Palay et al 2012, Storey et al 2014, O 4+ and O 5+ (Elabidi & Sahal-Bréchot 2013), Ne 4+ (Dance et al 2013), Mg 2+ and Al 3+ (Elabidi 2014), Mg 5+ (Tayal 2012a), Mg 7+ (Grieve et al 2013), Si + (Aggarwal & Keenan 2014b), Si 6+ (Sossah & Tayal 2014), Si 7+ (Tayal 2012b, S 2+ (Hudson et al 2012b, Grieve et al 2014, S 14+ and S 15+ including recombination (Mahmood et al 2012), Cl 2+ (Sossah & Tayal 2012), Ca 13+ (Dong et al 2012), Sc + (Grieve et al 2012) , Ni 17+ (Hudson et al 2012a), Ge + (Smirnov 2014), Nb +11 and Mo +12 (Liang et al 2014), Sn 13+ including ionization (Liu et al 2014b), W 3+ including ionisation (Ballance et al 2013), and Au 51+ (Fan et al 2014). …”