2008/05/20 by Hua-Yun Geng, Hua Y. Geng, Ying Chen +2 · 2 citations
Chemistry · Earth and Planetary Sciences · Materials Science · Physics and Astronomy · #Center (category theory) #Chemistry #Cluster (spacecraft) #Computer science #Crystallography #High-pressure geophysics and materials #Nuclear Materials and Properties #Oxygen #Physics #Quantum mechanics #Radioactive element chemistry and processing #Thermodynamics #cond-mat.mtrl-sci #cond-mat.str-el
paper · pdf · doi:10.1103/physrevb.77.180101
published as Phys. Rev. B 77, 180101(R) (2008) · 5 pages, 3 figures
openalex publication_date 2008/05/20 · arxiv created 2008/06/11 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
The stability mechanism of cuboctahedral clusters in nonstoichiometric uranium dioxide is investigated by first-principles local density approximation with Hubbard correction method. Calculations reveal that the structural stability is inherited from U6O12 molecular cluster, whereas the energy gain through occupying its center with an additional oxygen makes the cluster win out by competition with point oxygen interstitials. Local displacement of the center oxygen along the ⟨111⟩ direction also leads the cluster eightfolded degeneracy and increases relatively the concentration at finite temperatures. However, totally, elevation of temperature, i.e., the effect of entropy, favors point interstitial over cuboctahedral clusters.