Electronic structure and fine structural features of the air-grown UNxOy on nitrogen-rich uranium nitride

Chemical State of U in U–N–O Ternary System from First-Principles Calculations

“…The XPS results showed that there exist significant differences between UN and U 2 N 3 : UN shows the identical U 4f 7/2 peak with U metal, whereas the U 4f 7/2 peak of U 2 N 3 is significantly higher than that of U metal. In contrast to the results above, the U 4f 7/2 peak of UN x O y is within the range of 379.5–379.7 eV whereas that of fresh UN 2– x locates at 377.9 eV and that of UO 2 is 379.8 eV, as summarized in Table . From this table, there should be a higher OS, e.g., U 4+ and/or U 5+ , in UN x O y , as compared with formal OS of UN, and needs more clarification.…”

“…Interestingly, when the temperature exceeded 573 K, O in UN 1.66 and UN 1.42 O 0.23 films decreased significantly, whereas N increased due to the diffusion of N from the inner to outer layer. These findings suggest a diversified chemical formula of UN x O y , as evidenced by electron-energy-loss spectroscopy and first-principles calculations . Recently, Jin et al investigated the geometric, magnetic, electronic, and vacancy properties of bulk α-U 2 N 3 through first-principles calculation within DFT + U framework, as well as its reaction with oxygen .…”