Relativistic distorted-wave collision strengths for the $\mathbf 16\ \Delta n=0$ optically-allowed transitions with {$\mathbf n=2$}

Relativistic distorted-wave collision strengths have been calculated for the 16 $\Delta n=0$ optically-allowed transitions with $n=2$ in the 67 Be-like ions with nuclear charge number $Z$ in the range $26 \leq Z \leq 92$. The calculations were made for the four final, or scattered, electron energies $E'$ = 0.20, 0.42, 0.80, and 1.40, where $E'$ is in units of $Z^ {2}_{\rm eff}$ Ry with $Z_{\rm eff} = Z - 2.5$. In the present calculations we used an improved ``top-up'' method, the relativistic Kummer transformation (Fontes \& Zhang, Phys.~Rev.~A {\bf 76}, 040703(R) (2007)), to obtain high partial-wave contributions, in contrast to the semi- relativistic Coulomb-Bethe approximation used by Zhang \& Sampson (ADNDT {\bf 52}, 143 (1992)). More extensive collision strengths for Be-like ions were provided in this previous publication, including data for all of the possible 45 transitions, for six scattered energies and in 85 ions with $Z$ in the range $8 \leq Z \leq 92$. The collision strengths covered in the present work should be more accurate and are presented as replacements for the corresponding results in Zhang \& Sampson (1992).