Electronic-energy-band structure of uranium hydride

We have calculated the electronic energy bands of α and β UH3. These systems are unique among hydride formers in that a transformation directly to a trihydride occurs without an intervening dihydride phase and in that two trihydride structures form, both of which are based on the A-15 (V3Si) structure. We have found evidence of fairly large uranium f-electron-hydrogen s-electron bonding interaction which is allowed and favored by these structures. The β-UH3 has eight formula units in the unit cell with the hydrogens tetrahedrally coordinated. As usual there is a low-lying set (24) of hydrogen-derived states which overlaps the uranium f-levels. This leads to the result of two types of f-character: localized (magnetic) and itinerant. This latter type may be as large as one electron/U atom with a greater contribution from the linear chain atoms with a greater contribution from the linear chain atoms which form three of the four hydrogen neighbors than from the bcc-like uraniums. This makes the localized contribution more consistent with f1 and agrees more with the observed moment 1.18 μ/sub B/ than that expected for U4+