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

Abstract

In a recent paper, Goyal et al. [Can. J. Phys. {\bf 95} (2017) 1127] have reported results for collision strengths ($\Omega$) and effective collision strengths ($\Upsilon$) 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.