Abstract
The contribution to the ionization cross section of ionization-excitation processes by electron impact is usually negligibly small for low- and medium- elements. We demonstrate here, however, that for heavy atomic ions with the outermost shell being the ionization-excitation processes play an evident role in the ionization cross section. For the ground level of , the ionization-excitation cross section due to the excitation of levels in the configuration is comparable to the direct and ionization cross sections of and . The total ionization cross section will be underestimated by 15% without including the contribution from ionization-excitation processes. This is a general conclusion for heavy atomic ions, which is verified by taking Pd-like ions of , and as examples. The role of ionization-excitation processes can be understood from the overlapping of the wave functions between the and orbitals.
- Received 22 August 2014
DOI:https://doi.org/10.1103/PhysRevA.90.044701
©2014 American Physical Society