LAUSR

The influence of Ga on the adsorption and solubility of H on Ga-stabilized δ-Pu alloys is investigated using density functional theory and experimentally via a Sieverts’ apparatus. All-electron DFT calculations, with spin-orbit coupling and full relaxations of the surface, are implemented to calculate H adsorption on δ-Pu-Ga alloy (111) surfaces. Chemisorption energies indicate that H prefers a threefold hollow site that binds strongly to a Pu-rich environment regardless of Ga concentration of the surface. Sites that include a Ga-H bond yield an increase in chemisorption energies as opposed to chemisorption energies when the H is only bonded to Pu atoms. Also solution energies for interstitial sites are less exothermic than surface adsorption energies. Experimentally, H-vacancy binding is more exothermic than interstitial binding, and since vacancy binding is the analog of surface binding, the DFT results are in agreement. Both DFT and experimental results show that with increasing Ga content to 7 at. % G...