Chapter Seven - The Dielectric Formalism for Inelastic Processes in High-Energy Ion–Matter Collisions

Abstract

Abstract In this chapter we analyze the possibilities and ranges of validity of the dielectric formalism to deal with correlated bound electrons in matter by using the shellwise local plasma approximation. This model describes the response of the electrons of the same binding energy as a whole (collectively), screening the interaction with the impinging ion. It considers separately each sub-shell of target electrons, with the corresponding dielectric response. The density of electrons and the energy gap are included explicitly by employing the Levine and Louie dielectric function. The goal of this chapter is to summarize and review the capability of this model to deal with fundamental magnitudes of the atomic collisions expressed as different moments of the energy loss: ionization cross sections (single or multiple, differential, and total), stopping power (and mean excitation energy), and energy loss straggling. This review covers a wide range of the collisions of ions with gases and solids, paying special attention to multi-electronic targets. The advantages and disadvantages of the model in comparison with independent electron ones, ranges of validity and future prospect will be considered.