Comment on “Collision strength and effective collision strength for Br XXVII” by Goyal et al. [Can. J. Phys. 95, 1127 (2017)]

Abstract

In a recent paper, Goyal et al. [Can. J. Phys. 95, 1127 (2017)] have reported results for collision strengths (Ω) and effective collision strengths (ϒ) for transitions among the lowest 52 levels of F-like Br XXVII. For their calculations, they have adopted the Dirac atomic R-matrix code (DARC) and the flexible atomic code (FAC). In this comment we demonstrate that their results for both parameters are erratic, inaccurate, and unreliable.