Application of the relativistic DV-Xα molecular orbital method to γ-uranium alloys with transition metals

The alloying behavior of 4d and 5d transition metals (TMs) in γ-phase solid uranium (U) has been investigated using the discrete-variational Dirac–Fock–Slater (DV-DFS) method. We examined the d-orbital energy (Md value) of these TMs, the orbital overlap population (OOP) between the d-orbital of these TMs and the 5f or 6d orbital of γ-U, and the effective charge on each atom of the γ-U/TM alloy, and the effect of these parameters on alloying. It was found that the maximum solid solubility (MSS) of TMs into γ-U was exponentially proportional to both the Md and the OOP (U5f–TMd and U6d–TMd), except for Ta and W elements. We found a good correlation between the MSS and Md, the effective charge, or OOP.