Systematic study of the L-subshell ionization cross sections of Ho, Er, and Tm by MeV alpah 0article bombardments

摘要

The experimental L-subshell ionization cross sections, induced by MeV alpah particle bombardments, of Ho, Er, and Tm are compared with the ECPSSR theory. The general tendencies show systematic discrepancies for the three subshells. To account for the effects of induced intrashell transitions, the coupled state model is incorporated whtin the ECPSSR calculations, thus yielding the ECPSSR-IS. Systematic discrepancies between the predictions of the ECPSSR-IS and the expeirmental emasurements are s8gnificantly reduced. Yet, velocity independent discrepancies remain, attributed primarily to the overestimation of the electronic binding energies. The ECPSSR-IS is recalculated at binding e nergies correspond to the united atom, thus yielding The ECPSSR-IS-UA. The later model is capable of describing the experimental ionization cross sections for the L_2 and the L_3 subshells over all energies, but a significant discrepancy remains for the L_1 subshell. The reasons for the L_1-subshell discrepancy are discussed and proved.