Scaled collision strengths for hydrogenic ions

Scaled hydrogenic ion collision strengths Z 2Ω/sub H/ and Z 2Ω/sub H//sup e/ have been calculated using the Coulomb-Born-Oppenheimer approximation for the limit Z → infinity or, equivalently, time-dependent perturbation theory with the perturbation consisting of the entire electrostatic interaction between the electrons. The results are given for all transitions n/sub a/l/sub a/ → n'/sub a/l'/sub a/ from the sublevels with n/sub a/ = 1, 2, and 3 to those with n'/sub a/ = n/sub a/+1 and n/sub a/+2 for eight impact electron energies epsilon in threshold units in the range 1< or =epsilon< or =10. Approximate collision strengths for many important transitions in He-like and Li-like ions can be obtained from these results for Z 2Ω/sub H/ and Z 2Ω/sub H//sup e/. The results for Z 2Ω/sub H/ and Z 2Ω/sub H//sup e/ are fitted to simple functions of epsilon that are readily integrated over a Maxwellian to obtain collision rates