2005 Volume 46 Issue 6 Pages 1100-1102
In order to determine the band gap and quasiparticle energies of lithium chloride crystal accurately, we employ the state-of-the-art GW approximation on the basis of many-body-perturbation-theory at the ab initio level. Our method is based on the all-electron mixed-basis approach. We use the 2×2×2 supercell in which four lithium and four chlorine atoms exist. We demonstrate the importance of the q point sampling for the momentum transfer q of the Coulomb matrix elements. The result for the direct band gap at the Γ point compares well with experiment and the previous calculations.
