Electronic structure of the actinide-Rh3systems and the 5flocalization inUPd3

We present electronic-structure calculations for the isostructural (${\mathrm{AuCu}}_3$-structure) series of intermetallic compounds A${\mathrm{Rh}}_3$ (A=Ac, Th, Pa, U, Np, Pu, Am, and Cm). The calculations were performed using both the scalar relativistic and the fully relativistic linear muffin-tin orbital (LMTO) method. Calculated cohesive and magnetic properties are compared with available experimental data. The onset of magnetism is discussed by means of a relativistic Stoner theory. The influence of the ligand states on the uranium 5f electrons is studied for the U$M_3$ (M=Mo, Tc, Ru, Rh, Pd, and Ag) series of compounds. The localization of the 5f electrons in ${\mathrm{UPd}}_3$ as opposed to the itinerant 5f behavior for the earlier compounds (${\mathrm{UMo}}_3$, ${\mathrm{UTc}}_3$ , ${\mathrm{URu}}_3$, and ${\mathrm{URh}}_3$) is explained in terms of the variation of the hybridization between 5f and ligand 4d states through the series.