A charge-optimized many-body potential for the U-UO2-O2 system.
J Phys Condens Matter
; 25(50): 505401, 2013 Dec 18.
Article
em En
| MEDLINE
| ID: mdl-24275484
ABSTRACT
Building on previous charge-optimized many-body (COMB) potentials for metallic α-U and gaseous O2, we have developed a new potential for UO2, which also allows the simulation of U-UO2-O2 systems. The UO2 lattice parameter, elastic constants and formation energies of stoichiometric and non-stoichiometric intrinsic defects are well reproduced. Moreover, this is the first rigid-ion potential that produces the correct deviation of the Cauchy relation, as well as the first classical interatomic potential that is able to determine the defect energies of non-stoichiometric intrinsic point defects in UO2 with an appropriate reference state. The oxygen molecule interstitial in the α-U structure is shown to decompose, with some U-O bonds approaching the natural bond length of perfect UO2. Finally, we demonstrate the capability of this COMB potential to simulate a complex system by performing a simulation of the α-U + O2 â UO2 phase transformation. We also identify a possible mechanism for uranium oxidation and the orientation of the resulting fluorite UO2 structure relative to the coordinate system of orthorhombic α-U.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Urânio
/
Compostos de Urânio
/
Modelos Químicos
Idioma:
En
Ano de publicação:
2013
Tipo de documento:
Article