Ab initio calculation of the exchange-correlation kernel in extended systems -: art. no. 165108

We develop a method to calculate the polarizability of a many-electron system within Green's function theory in a similar way as within time-dependent density functional theory and apply it to Si and GaAs. The method joins the computational simplicity of the latter with the accuracy of the former approach. The resulting exchange-correlation many-body kernel f(xc)(FQP) and optical spectra are in good agreement with those obtained by the solution of the Bethe-Salpeter equation.