%0 Journal Article
%A Vásquez, G. C.
%A Maestre Varea, David
%A Cremades Rodríguez, Ana Isabel
%A Ramírez Castellanos, Julio
%A Magnano, Elena
%A Nappini, Silvia
%A Karazhanov, Smagul Zh.
%T Understanding the effects of Cr doping in rutile TiO₂ by DFT calculations and X-ray spectroscopy
%D 2018
%@ 2045-2322
%U https://hdl.handle.net/20.500.14352/12182
%X The effects of Cr on local environment and electronic structure of rutile TiO₂ are studied combining theoretical and experimental approaches. Neutral and negatively charged substitutional Cr impurities Cr_(Ti)(0)* and Cr_(Ti)(-1)*  as well as Cr-oxygen vacancy complex 2Cr_(Ti) + V₀ are studied by the density functional theory (DFT) within the generalized gradient approximation (GGA) of Perdew-Burke-Ernzerhof (PBE) functional. Experimental results based on X-Ray absorption spectroscopy (XAS) and X-Ray photoelectron spectroscopy (XPS) performed on Cr doped TiO₂ at the Synchrotron facility were compared to the theoretical results. It is shown that the electrons of the oxygen vacancy tend to be localized at the t_(2g) states of the Cr ions in order to reach the stable oxidation state of Cr(3+)*. Effects of Cr on crystal field (CF) and structural distortions in the rutile TiO₂ cell were analyzed by the DFT calculations and XAS spectra revealing that the CF and tetragonal distortions in TiO₂ are very sensitive to the concentration of Cr.
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