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 $f_{\mathrm{xc}}^{\mathrm{FQP}}$ and optical spectra are in good agreement with those obtained by the solution of the Bethe-Salpeter equation.

• Received 14 February 2003

DOI:https://doi.org/10.1103/PhysRevB.68.165108