Comprehensive and critically assessed cross sections for the electron-impact excitation and ionization of ground state and excited helium atoms are presented. All states (atomic terms) with ≤ 4 are treated individually, while the states with ≥ 5 are considered degenerate. For the processes involving transitions to and from ≥ 5 levels, suitable cross section scaling relations are presented. For a large number of transitions, from both ground and excited states, convergent close coupling calculations were performed to achieve a high accuracy of the data. The evaluated/ recommended cross section data are presented by analytic fit functions, which preserve the correct asymptotic behavior of the cross sections. The cross sections are also displayed in graphical form.

doi.org/10.1016/j.adt.2007.11.003
Atom. Data Nuc. Data Tab.

Ralchenko, Yu, Janev, R. K, Kato, T, Fursa, D. V, Bray, I, & de Heer, F. J. (2008). Electon-impact excitation and ionization cross sections for ground state and excited helium atoms. Atom. Data Nuc. Data Tab., 94, 603–622. doi:10.1016/j.adt.2007.11.003