On the electronic structure of CmFn (n=1-4) by all-electron Dirac-Hartree-Fock calculations

All-electron Dirac-Hartree-Fock calculations were performed to investigate the electronic structure of curium fluoride molecules (CmFn, n = 1-4). The curium-fluorine distances, atomization energies, and Mulliken populations were all evaluated. The bonding was found to be of ionic type with the electron delocalization primarily from F 2p to Cm 6d, where the formal configurations of Cm were 7s(2)5f(7), 5f(7)7s(1), 5f(7), 5f(6) for n = 1, 2, 3, 4, respectively. The 2p-6d delocalization is significant in the tetrafluoride. For comparison, the isovalent gadolinium fluorides were also studied. CmF4 exists but GdF4 does not, reflecting the fact that 5f(7) in CmF3 is less stable than 4f(7) in GdF3. (C) 2003 American Institute of Physics.