Optimal representation of the polarization propagator for large-scale GW calculations

Quasiparticle calculations based on the GW approximation are enhanced by introducing an optimal basis set for the polarization propagator, based on a Wannier representation of the one-electron wave functions, thus allowing the treatment of substantially larger systems. Our method is validated by calculating the vertical ionization energies of the benzene molecule and the band structure of bulk silicon. Its potentials are then demonstrated by addressing the quasiparticle spectrum of a model structure of vitreous silica, as well as of the tetraphenylporphyrin molecule.