Density functional study of O2 molecule and O atom adsorption on α-U(0 0 1) surface

Abstract

First-principle calculations have been performed to study both O2 molecule and O atom adsorption on α-U(001) surface and subsurface. The results show that the long-bridge site is the most stable adsorption site for O2U(001) and OU(001) surface adsorption. The tetrahedral (Tet) 1 site is the most stable adsorption site for OU(001) subsurface adsorption. The partial electronic density of states (PDOSs) of O2U(001) and OU(001) shows the hybridization of U and O atoms orbitals causes the electrons of 5f/6d of U more non-local and leads to the formation of OU bond. The OU bond is partly ionic and partly covalent. The analysis of the diffusion path of O atom on U(001) shows that O atom can easily transfer from hollow (hol) 1 site to hollow 2 site with no energy barrier. O atom can hardly transfer from surface to the subsurface.