2008/06/30 by Hua-Yun Geng, Hua Y. Geng, Ying Chen +2
Chemistry · Engineering · Materials Science · Physics and Astronomy · #Ab initio #Ab initio quantum chemistry methods #Chemical physics #Chemistry #Cluster analysis #Computer science #Condensed matter physics #Crystal structure #Crystallographic defect #Crystallography #Materials science #Mechanism (biology) #Metallurgy #Molecule #Neutron #Neutron diffraction #Nuclear Materials and Properties #Nuclear physics #Nuclear reactor physics and engineering #Oxygen #Physics #Quantum mechanics #Radioactive element chemistry and processing #Thermodynamics #Uranium #Uranium dioxide #Work (physics) #cond-mat.mtrl-sci #cond-mat.str-el
paper · pdf · doi:10.1063/1.3035846
published as Appl. Phys. Lett. 93, 201903 (2008) · 4 pages, 3 figures, title changed
arxiv created 2008/07/11 · openalex publication_date 2008/11/17 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
Oxygen defect clustering in uranium dioxide had been indicated in powder neutron diffraction measurements, and an empirical clustering mechanism had been proposed to explain the data. However, using first-principles LSDA+U calculations, we find that this empirical model, in fact, cannot work. A more physically reasonable model is proposed based on a thermodynamical competition between point defects and cuboctahedral clusters. This mechanism interprets the puzzled origin of the observed asymmetric interstitial O′ and O″ naturally. It also gives a good and consistent agreement with all available experimental data, except the high occupation of the O″ site.