Energy band calculations itinerant electrons

In the following sections we present the dHvA results of the lanthanide compounds shown in table 2, which are compared to the results of energy band calculations. Comparisons of the dHvA experiments with band calculations are essentially important to determine the f character, namely whether the 4f electrons are itinerant or localized. These Fermi surface properties should shed light on the basic understanding of the strongly correlated 4f-electron system. 

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). 

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