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O: Oberflächenphysik
O 37: Zeitaufgelöste Spektroskopie I
O 37.5: Vortrag
Donnerstag, 11. März 2004, 16:45–17:00, H36
Treatment of many-body effects in sodium clusters by means of GW theory — •Yaroslav Pavlyukh and Wolfgang Hübner — FB Physik, TU Kaiserslautern, D-67663 Kaiserslautern, Germany
The GW approximation for the calculation of electronic properties of systems without translational invariance like clusters or molecules is presented. In our implementation of the GW approximation we use the expansion of all quantities in gaussian type basis functions. The Green function, screened interaction, and self-energy are represented on the real axis of the frequency domain. The dielectric function is treated without any simplifications, such as the plasmon pole approximation. Convolutions are performed using fast Fourier transforms to the real time and back. We apply our approach to the range of Nan clusters (n=9-25). We present ionization potentials, electron affinities, band-gaps, plasmon energies, and life-times of quasiparticle states and collective excitations, which shows exellent agreement with experiments and other theories, such as TDLDA. A partially self-consistent GW calculation on Na9+ cluster enables us to improve the HOMO-LUMO gap (4.5 eV – HF, 3.7 eV – G0W0, 3.37 eV GW) and to determine the plasmon width and lifetime (2 eV and 4.1 fs, respectively).