Berlin 2008 – wissenschaftliches Programm
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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 4.4: Vortrag
Freitag, 29. Februar 2008, 11:00–11:15, A 151
Accurate description of the bonding of C6H6 at noble metal surfaces, using a local exchange-correlation correction scheme — •Erik McNellis, Karsten Reuter, and Matthias Scheffler — Fritz-Haber-Institut, Faradayweg 4-6, D-14195 Berlin (Germany)
The adsorption of benzene (C6H6) at the close-packed Cu(111) surface is a much studied model system for the interaction of larger π-conjugated molecules with solid surfaces. At first glance a rather simple system, the suspected predominantly van der Waals type bonding at the extended metal surface poses a severe challenge for accurate first-principles calculations. Density-Functional Theory (DFT) with local and semi-local exchange-correlation (xc) functionals is uncertain to properly account for this type of bonding, while the system sizes required to correctly grasp the metallic band structure quickly become computationally untractable with correlated wave function techniques. We overcome these limitations with a recently introduced "local xc correction" scheme [1], correcting the deficiencies in the adsorption energetics from present-day DFT xc functionals with hybrid functional and Møller-Plesset perturbation theory calculations for small clusters. From the obtained convergence of the xc correction with cluster size we can disentangle the short-range and dispersion type contributions to the bonding of the molecule at different heights above the surface. This enables us to qualify the role played by the two contributions in determining the binding energetics and geometry. [1] Q.-M. Hu, K. Reuter, and M. Scheffler, PRL 98, 176103 (2007) and 99, 169903 (2007); C. Tuma and J. Sauer, CPL 387, 388 (2004).