Photoemission scattering cross sections

The interpretation of photoemission spectra of the valence band is straightforward in the itinerant limit. In this case the band states are spread across the N unit cells of the crystal and the change in electronic density in a single unit cell is proportional to 1 /N and should be negligible. Then the band energies represent well the excitation spectrum if the appropriate scattering cross-sections are taken into account. This is the case of compounds with a broad 5f band, where the photoemission spectra correlate well with the results of band-structure calculations (Naegele et al. 1988). 

Many experimental methods for studying H and H induced effects on metals are known. Most of them are used for surface and adsorption studies in general, a few of them, however, are specific to H on metals. The direct detection of H on metals by some surface sensitive methods is rather difficult because of the low atomic number of H. Auger electron emission e.g. does not work principally, photoemission has extremely low cross section and X-ray scattering is very weak even at grazing incidence. Thus, in many cases, one does not analyze H directly but the H induced variations of the substrate properties. (See also Malinowski, 1983). 

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