The shellwise local plasma approximation, a collective model to describe bound electrons

C. C MONTANARI; D. M. MITNIK; J. E. MIRAGLIA

Itapema

Congreso; 20th International Conference on Ion Beam Analysis; 2011

International Committee of the 20th International Conference on Ion Beam Analysis

The SLPA is a general method to calculate the contribution of target bound electrons to the different moments of the energy loss (ionization cross sections, stopping, straggling) by performing a space integration of the values in a localized region. It is inspired in the seminal work by Lindhard and Scharff, and describes the response of the cloud of electrons of a certain shell as that of an inhomogeneous density of electrons with an ionization gap [1]. This SLPA is valid within the perturbative limit, i.e. linear response approximation within the dielectric formalism. The only inputs are the densities of the sub-shells and the corresponding binding energies. One of the advantages of the SLPA is that it deals with very heavy targets, like Au (79 electrons, 4f-subshell complete) with the same degree of complexity of much simpler ones, like C or Al. On the other hand, the same formalism is employed to describe bound electrons of solids or gas targets.