Quantum Prescription of Electron Energy Loss Spectroscopy in Crystalline Films

A quantum mechanical model is used to study the electron energy-loss spectroscopy (EELS) of crystalline noble metal films, which shows intrinsic features associated with their crystallographic orientation. Within the random-phase approximation, we employ a 1-D potential across the film that captures the main features of the electronic band structure of different facet orientation, and then accounting for the corresponding electron-spill out and the atomic-plane corrugation. Furthermore, we examine the role of the vertical transitions among quantum well states, which are related to the in-plane effective mass, which is typically used to fit the parabolic electron bands at the Fermi level.