Título:
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First-principles study of the optical transitions of F centersin the bulk and on the (0001) surface of (alpha)-Al2O3
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Autor/a:
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Carrasco Rodríguez, Javier; López, Núria (López Alonso); Sousa Romero, Carmen; Illas i Riera, Francesc
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Otros autores:
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Universitat de Barcelona |
Abstract:
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The electronic structure and spectroscopic features of the optical spectra of oxygen vacancies in the bulk and
on the 0001 surface of -Al2O3 have been studied by first-principles methods. The effect of oxygen vacancies
on the crystalline structure has been determined by the appropriate atomic structure optimization carried out
using a periodic model and density functional theory DFT calculations. Both, neutral F center and charged
F+ center oxygen vacancies have been considered. Optical transitions arising from the excitations of the
electron s trapped in the F+ and F centers, both on the surface and in the bulk of the material, have been
studied using a suitable embedded cluster model approach. The cluster geometry, including the relaxation
around the vacancy, has been taken from the periodic calculations. The transition energies and intensities have
been obtained by applying the explicitly correlated multiconfigurational second-order perturbation theory
method and also time-dependent DFT approaches. The present results are in good agreement with available
experimental data for the bulk and provide a guide to interpret forthcoming experiments involving the spectroscopy
of oxygen vacancies present in irradiated or defective -Al2O3 0001 surfaces. |
Materia(s):
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-Matèria condensada -Propietats òptiques -Estructura electrònica -Condensed matter -Optical properties -Electronic structure -Condensed matter |
Derechos:
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(c) The American Physical Society, 2005
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Tipo de documento:
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Artículo Artículo - Versión publicada |
Editor:
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The American Physical Society
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