Stopping power in heavy atoms, the role of 4f electrons

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

Helsinki

Conferencia; 29th international conference on atomic collisions in solids & 11th international symposium on swift heavy ions in matter; 2020

ICACS and SHIM

We present recent results for the stopping power of protons in solid Hf, Ta and Pt. Thesetargets have in common the 4f and 5p electrons as first subshells below the conduction band(free electron gas or FEG). We deal with these post-lanthanum heavy metals in three differentaspects. The first one is using a non-perturbative description for the energy loss in the FEG[1] based on the screening potential and the value of rs. The second one is using the dielectricformalism [2] for the stopping in the FEG in the energy region where plasmon excitations areimportant. The third one is a detailed description of the bound electrons by calculating thewave functions and binding energies using relativistic solutions of the Dirac equation for eachtarget. The stopping of bound electrons (1s-4f) is calculated using these wave functions andthe shellwise local plasma approximation (SLPA) [3,4]. We perform modifications to theusual SLPA to include inter-shell screening (5p-4f) and a local Mermin dielectric function [2].