Near Surface Stoichiometry in UO2: A Density Functional Theory Study
Joint Authors
Yu, Jianguo
Valderrama, Billy
Henderson, Hunter B.
Manuel, Michele V.
Allen, Todd
Source
Issue
Vol. 2015, Issue 2015 (31 Dec. 2015), pp.1-8, 8 p.
Publisher
Hindawi Publishing Corporation
Publication Date
2015-05-12
Country of Publication
Egypt
No. of Pages
8
Main Subjects
Abstract EN
The mechanisms of oxygen stoichiometry variation in UO2 at different temperature and oxygen partial pressure are important for understanding the dynamics of microstructure in these crystals.
However, very limited experimental studies have been performed to understand the atomic structure of UO2 near surface and defect effects of near surface on stoichiometry in which the system can exchange atoms with the external reservoir.
In this study, the near (110) surface relaxation and stoichiometry in UO2 have been studied with density functional theory (DFT) calculations.
On the basis of the point-defect model (PDM), a general expression for the near surface stoichiometric variation is derived by using DFT total-energy calculations and atomistic thermodynamics, in an attempt to pin down the mechanisms of oxygen exchange between the gas environment and defected UO2.
By using the derived expression, it is observed that, under poor oxygen conditions, the stoichiometry of near surface is switched from hyperstoichiometric at 300 K with a depth around 3 nm to near-stoichiometric at 1000 K and hypostoichiometric at 2000 K.
Furthermore, at very poor oxygen concentrations and high temperatures, our results also suggest that the bulk of the UO2 prefers to be hypostoichiometric, although the surface is near-stoichiometric.
American Psychological Association (APA)
Yu, Jianguo& Valderrama, Billy& Henderson, Hunter B.& Manuel, Michele V.& Allen, Todd. 2015. Near Surface Stoichiometry in UO2: A Density Functional Theory Study. Journal of Chemistry،Vol. 2015, no. 2015, pp.1-8.
https://search.emarefa.net/detail/BIM-1067323
Modern Language Association (MLA)
Yu, Jianguo…[et al.]. Near Surface Stoichiometry in UO2: A Density Functional Theory Study. Journal of Chemistry No. 2015 (2015), pp.1-8.
https://search.emarefa.net/detail/BIM-1067323
American Medical Association (AMA)
Yu, Jianguo& Valderrama, Billy& Henderson, Hunter B.& Manuel, Michele V.& Allen, Todd. Near Surface Stoichiometry in UO2: A Density Functional Theory Study. Journal of Chemistry. 2015. Vol. 2015, no. 2015, pp.1-8.
https://search.emarefa.net/detail/BIM-1067323
Data Type
Journal Articles
Language
English
Notes
Includes bibliographical references
Record ID
BIM-1067323