Theoretical study of plasmon losses in low-energy photoemission spectra

Abstract

We study the energy- and angular-dependence of bulk and surface plasmon losses in low- and intermediateenergy region (< 1000 eV), and investigate the applicability of the quantum Landau formula which can explain overall plasmon loss features accompanied by core level photoemission. As an example, we calculate the Al 2s photoemission in the photoelectron kinetic energy range from 60 to 1000 eV measured at normal to the surface and at small take-off angles (10° and 30°). For the normal emission the quantum Landau formula gives quite similar results to those without the high-enegy approximation even at 60 eV. On the other hand we observe the considerably large difference at the grazing angle emission (10?). Even at 30? we can safely apply the quantum Landau formula for the plasmon analyses above 250 eV. © 2012 The Surface Science Society of Japan.