Abstract
The interaction of atomic and molecular hydrogen with actinide dioxide (AnO 2 , An = U, Np, Pu) (111) surfaces has been investigated by DFT+U, where noncollinear 3k antiferromagnetic behaviour and spin-orbit interactions are considered. The adsorption of atomic hydrogen forms a hydroxide group, coupled to the reduction of an actinide ion. The energy of atomic hydrogen adsorption on the UO 2 (0.82 eV), NpO 2 (−0.10 eV), and PuO 2 (−1.25 eV) surfaces has been calculated. The dissociation of molecular hydrogen is not observed, shown to be due to kinetic rather than thermodynamic factors. As a barrier to the formation of a second hydroxyl group, an unusual charge distribution has been shown. This could be a limitation of a (1·1) unit cell method or an artefact of the systems. The recombination of hydrogen ions on the AnO 2 (111) surfaces is favoured over hydroxide formation.
Original language | English |
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Article number | 134701 |
Journal | Journal of Chemical Physics |
Volume | 150 |
Issue number | 13 |
DOIs | |
Publication status | Published - 7 Apr 2019 |
Bibliographical note
Funding Information:This research was supported by the UK Engineering and Physical Science Research Council (EPSRC) (Grant Nos. EP/G036675 and EP/K016288) and the Atomic Weapons Establishment (AWE). A.E.S. gratefully acknowledges the United States Department of Homeland Security (DHS), Domestic Nuclear Detection Office (DNDO), National Technical Nuclear Forensics Centre (NTNFC) for a Postdoctoral Research Fellowship. N.H.d.L. thanks the Royal Society for an Industry Fellowship and AWE for a William Penney Fellowship. This work made use of the ARCHER UK National Supercomputing Service (http://www.archer.ac.uk), via our membership of the UK’s HEC Materials Chemistry Consortium, which is funded by EPSRC (Grant No. EP/L000202).
Publisher Copyright:
© 2019 Crown.
ASJC Scopus subject areas
- General Physics and Astronomy
- Physical and Theoretical Chemistry