Berlin 2008 – scientific programme

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SYEC: Symposium Exact-exchange and hybrid functionals meet quasiparticle energy calculations

SYEC 4: Exact-exchange and hybrid functionals meet quasiparticle energy calculations IV

SYEC 4.5: Talk

Friday, February 29, 2008, 11:15–11:30, A 151

Large scale GW calculations of Na cluster on the Cu(001) surface — •Yaroslav Pavlyukh and Jamal Berakdar — Institut für Physik, Martin-Luther-Universität Halle-Wittenberg, Heinrich-Damerow-Str. 4, 06120 Halle

Application of the many-body perturbation theory to realistic systems relies on the knowledge of single- and two-particle correlation functions. The Configuration Interaction (CI) approach widely adopted in quantum chemistry provides information on the excited states of the system and, thus, allows to compute the screened Coulomb interaction (a 2-particle quantity) from first principles. In this way one can systematically go beyond the random phase approximation (RPA). This is beneficial for finite systems such as molecules or clusters where the screening is more complex than in bulk systems. We developed a theory that combines the CI and Green’s function methods and applied it to realistic systems. In particular, we studied the screened Coulomb interaction which provides access to the life-times of quasiparticle states. Our investigation of the adsorption of Na₉⁺ cluster on a Cu(001) surface shows that the life-times of the hybridized single-particle states drastically depend on the geometry of the system. This indicates a change in electronic correlations upon adsorption and suggests that only ab initio methods can provide an adequate description of the experiment.