Development of a new method for the quantitative analysis of energy loss spectra of fast electrons scattered in the direction of the incident beam: application to the study of noble metals

A doubly iterative calculation allows for the separation, in the energy loss spectra obtained in the direction of the incident beam, of the contributions from single volume and surface scattering from those of multiple scattering contributions. The complex dielectric constant, deduced from the volume term after normalization and Kramers-Kronig analysis, enables the calculation of standard optical functions (notably the photoabsorption coefficient and dipole oscillator strengths) over a significant energy range (2 to 200 eV or more), with the quality of the results remaining practically constant across the entire explored energy domain. The application to noble metals (Cu, Ag, Au) demonstrates the quality of the results in relation to various optical measurements and illustrates its potential both in understanding energy loss mechanisms and in studying the structures of weakly bound electrons.