Regensburg 2007 – scientific programme

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MM: Fachverband Metall- und Materialphysik

MM 25: Electronic properties II

MM 25.3: Talk

Wednesday, March 28, 2007, 15:15–15:30, H6

Conserving GW calculations for small metal clusters — •George Pal, Yaroslav Pavlyukh, Hans Christian Schneider, and Wolfgang Hübner — Fachbereich Physik, Technische Universität Kaiserslautern, P.O. Box 3049, 67663 Kaiserslautern, Germany

We present a GW-like approach for the quasiparticle energies and lifetimes of the closed-shell Na₄, Na₉⁺ and Na₂₁⁺ clusters. The screened Coulomb potential is constructed directly from the density-density correlation function, which is the functional derivative of a conserving single-particle Green’s function with respect to an external potential. The density-density correlation function is obtained numerically by solving a quantum kinetic equation for the linear response of the system subject to a weak external perturbation. The conserving nature of our approach is shown by explicitly evaluating the f-sum rule. Analyzing the quasiparticle spectral functions, we find pronounced differences in the peak positions and broadenings when comparing our results with the self-consistent GW-RPA approach, which is not conserving at the two-particle level.