title: Interplay between single-particle and plasmonic excitations in the electronic response of thin Ag films.
abstract: High-resolution electron energy loss spectroscopy is used to study the electronic properties of thin Ag layers on Ni(111). In addition to the ordinary surface plasmon at 3.8 eV, we observe a broad feature at 7-8 eV, whose nature is investigated as a function of scattering geometry and primary electron beam energy. Loss measurements unambiguously indicate that this mode has spectral components from both free-electron Ag plasmonic excitations (free-electron surface plasmons and multipole plasmons) and single-particle transitions.
authors.affiliation: Dipartimento di Fisica, Università degli Studi della Calabria, I-87036 Rende (Cs), Italy.
authors.forename: A
authors.initials: A
authors.lastname: Politano
authors.forename: V
authors.initials: V
authors.lastname: Formoso
authors.forename: G
authors.initials: G
authors.lastname: Chiarello