Dresden 2009 – scientific programme

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O: Fachverband Oberflächenphysik

O 42: Poster Session II (Nanostructures at surfaces: arrays; Nanostructures at surfaces: Dots, particles, clusters; Nanostructures at surfaces: Other; Nanostructures at surfaces: Wires, tubes; Metal substrates: Adsorption of O and/or H; Metal substrates: Clean surfaces; Metal substrates: Adsorption of organic/bio moledules; Metal substrates: Solid-liquid interfaces; Metal substrates: Adsorption of inorganic molecules; Metal substrates: Epitaxy and growth; Heterogeneous catalysis; Surface chemical reactions; Ab-initio approaches to excitations in condensed matter; Organic, polymeric, biomolecular films– also with adsorbates; Particles and clusters)

O 42.105: Poster

Wednesday, March 25, 2009, 17:45–20:30, P2

Optical Spectra and Band Structure of Anatase and Rutile TiO₂ — •Andreas Greuling¹, Patrick Rinke², and Michael Rohlfing¹ — ¹Universität Osnabrück, Barbarastr.7,D-49069,Osnabrück — ²University of California, Santa Barbara

TiO₂ is a semiconductor which is used in many applications (e.g. in biotechnology, cosmetic industry, paint industry, in catalysis or photocatalysis). Therefore, the (optical) properties of TiO₂ are of great interest. As these are still not fully understood in theory we address its excited electronic states and optical spectra with ab initio methods beyond DFT.

We present results of first principles calculations for anatase und rutile TiO₂. Starting from the electronic ground state, which is calculated within DFT(LDA), we describe the single particle excitations with an GWA approach. We use Gaussian basis-sets because this results in reasonable computational cost. Then we calculate the electron-hole interaction and solve the Bethe-Salpeter Equation (BSE) in order to obtain coupled electron-hole excitations. Based on the resulting data we evaluate the optical spectra and compare them with experimental data.