Relativistic distorted-wave collision strengths for the optically allowed transitions with in the 67 Be-like ions with

Relativistic distorted-wave collision strengths have been calculated for the 16 Δ n = 0 optically allowed transitions with n = 2 in the 67 Be-like ions with nuclear charge number Z in the range 26 ≤ Z ≤ 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 eff 2 Ry with Z eff = Z − 2.5 . In the present calculation, an improved “top-up” method, which employs relativistic plane waves, was used to obtain the high partial-wave contribution for each transition, in contrast to the partial-relativistic Coulomb–Bethe approximation used in previous work by Zhang and Sampson [H.L. Zhang and D.H. Sampson, At. Data Nucl. Data Tables 52 (1992) 143]. In that earlier work, collision strengths were also provided for Be-like ions, but for a more comprehensive data set consisting of all 45 Δ n = 0 transitions, six scattered energies, and the 85 ions with Z in the range 8 ≤ Z ≤ 92 . The collision strengths covered in the present work should be more accurate than the corresponding data given by Zhang and Sampson [H.L. Zhang and D.H. Sampson, At. Data Nucl. Data Tables 52 (1992) 143] and are presented here to replace those earlier results.