X-ray Photoemission from Core Electrons in Solids

Abstract

The energies of outer electrons of atoms in solids are broadened into bands, and our knowledge of the shape of these bands has been increased very considerably during the past few years by measurements of their photoelectron spectra. The spectra may be excited by uv or x-radiation, although it is generally recognized that excitation by x-rays, where the electron final state lies in the continuum, gives a more direct picture of the density of states versus energy curve than uv excitation, where the electron may finish up in an empty band state. It is found that conduction or valence bands are several eV in width and that their density of states curves may show considerable structure.