  The electron-phonon interaction in thin Ag-nanofilms epitaxially grown on
Cu(111) is investigated by temperature-dependent and angle-resolved
photoemission from silver quantum-well states. Clear oscillations in the
electron-phonon coupling parameter as a function of the silver film thickness
are observed. Different from other thin film systems where quantum oscillations
are related to the Fermi-level crossing of quantum-well states, we can identify
a new mechanism behind these oscillations, based on the wavefunction
localization of the quantum-well states in the film.
