Effective collision strengths for transitions in Ni  XIX

Abstract

Aims. In this paper we report electron impact collision strengths and excitation rates for transitions among the lowest 89 levels of Ni xix.Methods. The Dirac atomic R-matrix code (darc) is adopted for the calculations of collision strengths and subsequently the effective collision strengths. Results. Collision strengths for resonance transitions among 89 levels arising from the (1s 2 ) 2s 2 2p 6 , 2s 2 2p 5 3 , 2s2p 6 3 , 2s 2 2p 5 4 , and 2s2p 6 4 configurations of Ni xix are reported over a wide energy range below 250 Ryd. Additionally, effective collision strengths for all 3916 transitions among the 89 levels are listed over a wide temperature range below 10 7 K. Comparisons are made among different calculations and the accuracy of the data is assessed. Finally, comparisons between theoretical and experimental intensity ratios of some prominent lines of Ni xix are discussed.

Energy levels and radiative rates for transitions in Cr-like Co IV and Ni V

“…Similar data for several Ni ions have also been reported, i.e. Ni XI [10], Ni XIII -Ni XVI [11], Ni XVII [8], Ni XIX [2], Ni XXIII [7], Ni XXVI [4], Ni XXVII [6], and Ni XXVIII [5]. Here we focus our attention on Cr-like Co IV and Ni V.…”

“…Since there is a paucity of measured parameters, one must depend on theoretical results. Therefore, over the last few years we have reported atomic parameters for many ions of the iron group elements -see for example [1][2][3][4] and references therein. Among Co ions, results have already been provided for Co XXVII [5], Co XXVI [6], Co XXV [4], Co XXII [7], Co XVI [8], and Co XI [9].…”

Radiative rates for E1, E2, M1, and M2 transitions in Ne-like Cu XX, Zn XXI and Ga XXII

“…However, to interpret observations or to model the plasmas, information is required for several atomic parameters, such as energy levels, radiative rates and collision strengths. Therefore, over a period of time we have reported atomic data for a few Ne-like ions, namely Cl VIII [2], Fe XVII [3,4], Ni XIX [5,6], and very recently W LXV [7]. Similarly, many other workers have reported data for Ne-like ions.…”

Radiative rates for E1, E2, M1, and M2 transitions in Ne-like Hf LXIII, Ta LXIV and Re LXVI

“…Emission lines of several Ne-like ions (particularly of Fe XVII and Ni XIX) among lower Z elements (up to 36) have been prominently observed in a variety of astrophysical plasmas and have been useful for diagnostics [1][2][3][4], for which atomic data for several parameters, such as energy levels, radiative rates and collision strengths, are required. Therefore, a lot of attention has been paid to these ions -see for example Jönsson et al [5] and references therein.…”