  A theoretical study of the dynamical dielectric response of bulk lead at low
energies is presented. The calculations are performed with full inclusion of
the electron band structure calculated by means of a first-principles
pseudopotential approach. The effect of including the spin-orbit splittings in
the band structure is analyzed, together with dynamical exchange-correlation
and local-field effects. Excitations are studied in detail, showing the
presence at small momenta of acoustic-like dispersing excitations. The
character of these modes with sound-like dispersion depends on the direction of
the momentum transfer q. In general results show strong anisotropy effects on
the dielectric response of bulk Pb. Comparison with available optical
experimental data shows good agreement.
