Stopping power in very heavy targets: from lanthanides to posttransition metals

C. C. MONTANARI; MENDEZ, A.M.P.; J. P. PERALTA; MITNIK, D.M.

Congreso; 22 th INTERNATIONAL CONFERENCE ON ION BEAM MODIFICATION OF MATERIALS; 2022

The present state of the stopping data is discussed within the framework of the IAEA stoppingdatabase [1]. We focus on the need and importance of reliable values for very heavy targets,such as lanthanides, from lanthanum to lutetium, 6-period transition metals and post-transitionmetals. Full theoretical calculations are presented for the stopping power of protons in suchatomic solids. The importance of relativistic radial orbitals and binding energies is discussed,not only for the deep but also for the outer shells. The electronic stopping power is described bycombining three formalisms: i) the screened potential with cusp condition model [2] (SPCC),which is a non-linear binary formalism for the energy loss in the free electron gas (FEG); ii) thedielectric formalism [3] for the stopping in the FEG (in the energy region where plasmonexcitations are important); iii) the shellwise local plasma approximation (SLPA) [4] for thebound electron contribution. The comparison with the well-known SRIM [5], DPASS [6] andCASP [7] results is presented and discussed. We consider that present results are a picture ofthe state of art of the stopping in lanthanides and post-lanthanides and also states doubts of someof the experimental data in the IAEA database [1] and employed in the SRIM [5] semi-empiricaldescription.