The dynamic structure factor of simple metals : a study of the electronic correlation in solids

In this work we compare experimental inelastic X-ray scattering spectra and TDDFT results for sodium and aluminum. The effects due to the real lattice are not sufficient to bring the results significantly closer to the experimental ones than previous results for jellium. We show that an accurate description of electron correlations is also required to provide a reasonable agreement, espeaally in the case of sodium. TDDFT-TDLDA with the inclusion of lifetime effects provides a good agreement for momentum transfer vertical bar q vertical bar smaller than 2 ge, only for larger vertical bar q vertical bar the agreement deteriorates. We will discuss the possibility of constructing an exchange-correlation kernel able to reproduce these lifetime effects.