  Li and Rosmej derived analytical fits for the energy level shifts due to
plasma screening on the basis of a free-electron potential published by Rosmej
et al. one year earlier. The derivation of the fits, which were shown by
Iglesias to be inconsistent with the fundamental premise of the ion-sphere
model, was motivated by the belief that no analytical expression exists for the
expectation value $\langle r^{3/2}\rangle$, an assertion that was also
contradicted by Iglesias. In this short note, I point out that a simple
expression for the latter quantity can be obtained as a particular case of a
formula published by Shertzer, and I provide a corresponding compact analytical
expression for the level shifts in the framework of Rosmej's formalism.
