Electron spectroscopy of surfaces

Electron spectroscopic methods can be applied to investigate the crystallography, the chemistry and the electronic structure associated with atoms in the outermost atomic layers of a solid. In this article the application of electron energy loss spectroscopy and photoelectron spectroscopy to investigate both occupied and unoccupied electronic states in solids are described. The recent development of synchrotron radiation sources and angularly resolving spectroscopic techniques has made the detection of surface states and resonances more straightforward and has enabled the dispersion of surface and bulk states to be investigated. Angularly resolving photoelectron spectroscopic techniques are also enabling information about the adsorption sites, the nature of the chemical bonding, and the orientation of atoms and molecules adsorbed on surfaces to be obtained. Examples are considered.