2013/07/02 by Sven P. Rudin, Rudin, Sven P.
Chemistry · Materials Science · Physics and Astronomy · #FOS: Physical sciences #Materials Science (cond-mat.mtrl-sci) #Nuclear Materials and Properties #Radioactive element chemistry and processing #Rare-earth and actinide compounds #cond-mat.mtrl-sci
paper · pdf · doi:10.48550/arxiv.1307.0764
13 pages, three figures
arxiv created 2013/07/02 · openalex publication_date 2013/07/02 · arxiv updated 2013/07/03 · openalex created_date 2024/04/11 · openalex updated_date 2026/07/28
Plutonium dihydride and trihydride show strikingly similar crystal structures when viewed as close-packed Pu planes with ABC and AB stacking, respectively. The similarity serves as a framework for density functional theory (DFT) calculations of PuH2, PuH3, and intermediate compositions. Agreement between structures observed in experiment and in the DFT description of the Pu-H system requires accounting for the strong electronic correlation in the f orbitals, achieved here with the addition of a Hubbard parameter U. The hysteresis measured between hydriding and dehydriding can be attributed to the effect of stacking of the close-packed Pu planes on the energy as a function of stoichiometry, calculated using the GGA+U approach. Changes in the interstitial positions occupied by the H atoms affect the energy by amounts that are negligible compared to room temperature; changes in the magnetic structure lead to equally small energy differences.