Berlin 2005 – wissenschaftliches Programm

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O: Oberflächenphysik

O 11: Elektronische Struktur I

O 11.1: Vortrag

Freitag, 4. März 2005, 15:45–16:00, TU EB420

Oxygen 1s NEXAFS spectra of differently terminated V₂O₃(0001) surfaces: ab initio DFT cluster studies for the V′OV and O_tV′O terminations — •Christine Kolczewski and Klaus Hermann — Fritz-Haber Institut der Max-Planck Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany

In the present work we use model clusters and ab initio density functional theory (DFT) together with gradient corrected functionals to obtain theoretical 1s core excitation spectra of differently coordinated oxygen appearing near the V₂O₃(0001) surface. Here we consider both the intrinsic half metal layer, V′OV, and the vanadyl termination, O_tV′O. Comparison of the theoretical spectra with those from recent NEXAFS experiments [1] spectra yields overall good agreement. This allows us to assign spectral details in the experiment to specific O 1s core excitations where final state orbitals are determined by the local binding of the differently coordinated oxygen centers. The strong dependence of peak positions and relative intensities on the photon polarization direction found in experiment is also described well by the present theoretical spectra. As a result, a combination of the present theoretical spectra with experimental NEXAFS data enables an identification of differently coordinated surface oxygen species at the V₂O₃(0001) surface.

[1] A.-C. Dupuis, M. Abu Haija, B. Richter, H. Kuhlenbeck, and H.-J. Freund, Surface Science, 2003, vol. 539(1-3), 99-112