Core-hole effect in the ELNES of alpha-Al2O3: experiment and theory.
The occurrence of the core-hole effect at the Al-K and Al-L1 edge in alpha-Al2O3 was studied by comparing experimental electron energy-loss near-edge structures (ELNES) and results of band-structure calculations with and without accounting for core-hole effects by the Z + 1 approximation. It was found that the theoretically calculated unoccupied p-like projected densities of states (PDOS) without Z + 1 approximation matches better to the experimental Al-L1 ELNES, whereas the PDOS with Z + 1 approximation matches better to the experimental Al-K ELNES. We conclude that the localisation of the initial state is an important prerequisite for the observability of the core-hole effect in the ELNES.
Max-Planck-Institut für Metallforschung, Stuttgart, Germany. nufer@hrem.mpi-stuttgart.mpg.de
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Nufer
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Gemming
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Elsässer
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Köstlmeier
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Rühle