ion-induced L x-ray emission cross sections of ytterbium

Measured L x-ray ionization cross sections for bombardment of Yb in the energy range 1.0 - 8.5 MeV are compared with the ECPSSR theory. Significant discrepancies between theory and experiment are observed at an incident beam energy below about 5 MeV. The discrepancies are greatly reduced by the inclusion of collision-induced intrashell coupling (ECPSSR-IS) and modifications of the binding factor in the theory in the united atom picture (ECPSSR-IS-UA). More specifically, in this case of Yb L-shell ionization by energetic ions, the contribution of L-subshell coupling towards better agreement with the theory is more significant than binding energy correction.