Ab initio and molecular orbital studies of the diuranium molecule

The existence and nature of actinide multiple bonds have been investigated by ab initio relativistic-core-potential SCF, MCSCF, and SRCI calculations on the diuranium molecule. These calculations indicate a double-minimum potential energy surface for diuranium, similar to that reported (and debated) for dichromium. At short bond lengths (2.2 angstrom), the lowest-energy state lies approximately 80 kcal/mol above the separated atoms. At longer bond distances, the 5f orbitals retain their atomic character, and six valence electrons occupy 6d and 7s MOs