Excitation and ionization of highly charged ions by electron impact. Progress report, December 15, 1976--December 15, 1977. [Cross sections

Abstract

The procedure for obtaining ionization results for highly charged complex ions from scaled or reduced ionization cross sections Q/sub R/sup H/(nl,u) for hydrogenic ions with Z = infinity was improved and the results compared with the available experimental data. It appears that the method is accurate to within approximately 20 to 30 percent for Z/N greater than or equal to 2, where N is the number of bound electrons per ion, and the accuracy improves as Z increases. Calculations of the reduced cross section Q/sub R/sup H/(3s,u) for ionization from the 3s sublevel were made, and a recommendation given for estimating Q/sub R/sup H(3p,u). With these results together with the previous results, the approximate cross sections for direct ionization from the 1s, 2s, 2p, 3s and 3p sublevels in any complex ion with Z/N greater than or equal to 2 are readily obtained. Results for the scaled hydrogenic ion excitation collision strengths Z/sup 2/..cap omega../sub H/ and Z/sup 2/..cap omega../sub H/sup e/ and R-matrix elements ZR/sub H/ have been completed for 29 transitions at 6 or more energies. With these it is believed that all of the basic hydrogenic ion excitation data likely to be required for application of themore » approach to obtain excitation collision strengths for highly charged complex ions. Currently these data are being used in calculating configuration mixed intermediate coupling collision strengths for fine structure transitions in Be-like ions with Z less than or equal to 50; and in ions with smaller values of N, as well. The results for He-like ions are mostly completed and in good agreement with a few more elaborate calculations made near threshold by Jones for transitions with n less than or equal to 2 in Fe/sup 24 +/ and Ca/sup 20 +/.« less