Excitation and ionization of highly charged ions by electron impact. Progress report, August 1, 1979-August 31, 1980

The reduced cross sections Q/sub R//sup H/(nl,u) have been calculated for ionization from the nl = 4s, 4p, 4d and 4f sublevels and the results fitted to simple functions of the impact electron energy u in threshold units. With these values plus those obtained in our earlier work results are now available for all the sublevels 1s, 2s, 2p, 3s, 3p, 3d, 4s, 4p, and 4f. From the values for Q/sub R//sup H/(nl,u) one can readily obtain the cross section for direct ionization from any of these sublevels in any highly charged complex ion using the simple procedures given in our earlier work. The total ionization cross section with inclusion of the excitation-autoionization contribution has been obtained for Be-like and Li-like ions. The results for the Li-like ions N4+ and 05+ are in generally good agreement with recent results of Crandall and co-workers. Basic hydrogenic ion data for scaled R-matrix elements and collision strengths have been calculated for the transitions 1s-2s, 2p, 3s, 3p, 3d; 2s, 2p-3s, 3p, 3d, 4s, 4p, 4d, 4f; and 3s, 3p, 3d-4s, 4p, 4d, 4f, 5s, 5p, 5d, 5f, 5g for the eight impact electron energies in threshold units epsilon = 1.0, 1.2, 1.5, 1.9, 2.5, 4.0, 6.0, and 10.0. Collision strengths and radiative line strengths for the Δn = 0 transitions in He-like and Be-like ions have been calculated for additional Z values so that results are now available for He-like ions with Z = 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 36, 42, 48, 54, 64 and 74 and for Be-like ions with the same Z values for Z greater than or equal to 12. All these collision strength data have been fitted to simple functions of the impact electron energy that are readily integrated over a Maxwellian to obtain collision rates. Preliminary results have been obtained for the n = 2 to n = 3 transitions in Be-like ions