Ground state electron configuration of element 111

The low-lying electronic states of element 111 are investigated by the relativistic coupled-cluster method based on the Dirac-Coulomb-Breit Hamiltonian. A large basis set (26s21? p? 16d9f7g5h) of Gaussian-type orbitals is used. In contrast to the lighter group 11 elements, the ground state of the atom is 6d97s2D522; the D322 state is higher by 2.69 eV, and the 6d107sS2 lies 2.95 eV above the D522. The reversal is ascribed to relativistic effects; without them, the S2 energy is 5.43 eV below the D2. The calculated electron affinity of the atom is 1.56 eV, and its ionization potential is 10.6 eV.