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Title: Electron-impact collision strengths for excitation of He-like ions from the levels with n = 1 and 2 to all singly excited levels with higher n< or =5

Journal Article · · At. Data Nucl. Data Tables; (United States)

Intermediate-coupling collision strengths have been calculated for all transitions of the kind 1s2p/sup 2S/+1P/sub J/-1sn'l'/sup 2S/'+1L'/sub J//sub '/ with n' = 3,4, and 5 and l'> or =1 (p, d, f, g) for 20 He-like ions with nuclear charge number Z in the range 4< or =Z< or =74. The method used is a Coulomb-Born-Exchange method that is especially well suited for calculating results for many members of an isoelectronic sequence simultaneously. The calculations were made for nine impact-electron energies in threshold units epsilon = 1.0, 1.2, 1.5, 1.9, 2.5, 4.0, 6.0, 10.0, and 15.0. The results are given in the form of fits to a simple function of epsilon that is readily integrated over a Maxwellian to obtain collision rates. The parameters required in obtaining collision strengths for the simpler transitions from the 1s2p levels to the 1sn's levels with 3< or =n'< or =5 and for the transitions from the ground level and the 1s2s levels to all singly excited levels with higher n values < or =5 are given, as well. Results for transitions between energy terms and their jj coupling analogs are also included. In addition, calculated values for the transition energies and the electric-dipole radiative line strengths are given for all transitions.

Research Organization:
Department of Astronomy, The Pennsylvania State University, University Park, Pennsylvania 16802
DOE Contract Number:
AC02-76ET53056
OSTI ID:
5092805
Journal Information:
At. Data Nucl. Data Tables; (United States), Vol. 29:3
Country of Publication:
United States
Language:
English