Mixed 5f atomic configurations in two polymorphic forms of uranium pentafluoride

• Published in: Chemical physics letters 2022-01, Vol.787, p.139240, Article 139240
• Main Authors: Li, Ru-song, Xie, Zheng, Qiu, Li-jun, Kong, Ling-Yun, Xin, Du-qiang
• Format: Article
• Language: English
• Subjects: Correlation effect; Dynamical mean-field theory; Impurity solver; Occupation number; Self energy
• ISSN: 0009-2614; 1873-4448
• DOI: 10.1016/j.cplett.2021.139240

[Display omitted] •Russel-Saunders coupling scheme might be more feasible for U 5f electron.•U j = 5/2 and j = 7/2 manifolds both are in weakly correlated states.•Occupation numbers of nf ∼ 2.002, 1.862 for U 5f electrons in α and β phases UF5.•Charge transfer, hybridization, and delocalization promote bonding of U 5f orbitals. A first principles calculation in this work is performed on two polymorphic forms of uranium pentafluoride (UF5) by using density functional theory (DFT) merging with dynamical mean-field theory (DMFT) scheme with spin–orbit coupling (SOC) and on-site Coulomb repulsion for correlation effect due to the incompletely filled U 5f orbitals. Calculation results suggest that U j = 5/2 and j = 7/2 manifolds both are in weakly correlated states in α and β phases UF5 and, Russel-Saunders (LS) coupling scheme is appropriate for U 5f electrons. Occupation probability analysis demonstrates that U ions are mostly composed of mixed atomic configurations 5f1, 5f2 and 5f3 with average occupation numbers of nf ∼ 2.002 and 1.862 for U 5f electrons in α and β phases UF5, respectively, mainly due to the complicated quantum mechanics processes including the dual nature of localized and itinerant U 5f electrons, as well as the flexible outer electronic configuration of U ions. Finally, we estimate the momentum-resolved electronic spectrum function (the so-called quasiparticle band structure) to compare with angle-resolved photoemission spectrum (ARPES).