Comment on "Collision strength and effective collision strength for Ba~XLVIII" by Mohan et al. [Can. J. Phys. 95 (2017) 173]

TL;DR

This paper critically evaluates the collision strength and effective collision strength data for Ba~XLVIII provided by Mohan et al., highlighting overestimations and reliability issues in their calculations, especially for $$ at lower temperatures.

Contribution

It provides a detailed critique of the accuracy of previously reported collision data for Ba~XLVIII, emphasizing the limitations of their $$ calculations.

Findings

Mohan et al.'s $$ results are overestimated for several transitions.

Their $$ calculations show non-physical behavior at lower temperatures.

The $$ data for allowed transitions are less reliable than the $\u03a9$ data.

Abstract

In a recent paper, Mohan et al. [Can. J. Phys. {\bf 95} (2017) 173] have reported results for collision strengths ($\Omega$) and effective collision strengths ($\Upsilon$) for transitions from the ground to higher 51 excited levels of F-like Ba~XLVIII. For the calculations of $\Omega$, the Dirac atomic $R$-matrix code (DARC) and the flexible atomic code (FAC) have been adopted, in order to facilitate a direct comparison. However, for the subsequent calculations of $\Upsilon$, DARC alone has been employed. In this comment, we demonstrate that while their limited results for $\Omega$ are comparatively reliable, for $\Upsilon$ are not, particularly for the allowed transitions and at lower temperatures. Apart from the non expected behaviour, their $\Upsilon$ values are overestimated for several transitions, by about a factor of two.