Ab-initio quasiparticle energies of small sodium clusters by the GW approximation

The quasiparticles energies of Na2 and Na4 are analyzed by carrying out ab initio GW approximation using an all-electron mixed-basis approach. The absolute value of quasiparticle energy of these clusters is discussed. The all-electron mixed-basis approach is a natural extension of the pseudopotential approach that takes into account full the core electrons.