Ground State Electron Configuration of Rutherfordium: Role of Dynamic Correlation

Abstract

The low-lying electronic states of ${\mathrm{Rf}}^{+}$ and Rf are investigated by the relativistic coupled cluster method based on the Dirac-Coulomb-Breit Hamiltonian. A large basis set ($34s24p19d13f8g5h4i$) of Gaussian-type orbitals is used. The external 36 electrons are correlated. In contrast with recent multiconfiguration Dirac-Fock (MCDF) results, the $7s^{2}6d^2{}_{}{}^3{}_{}{}^{}F_2^{}{}_{}{}^{}$ state is found to be the ground state of the atom, lying about 0.30 eV below the $7s^{2}7p6d{}_{}{}^3{}_{}{}^{}D_2^{}{}_{}{}^{}$ state (the MCDF ground state). The dynamic correlation of the system, requiring virtual orbitals with $l$ up to 6, is responsible for the reversal. The first ionization potential of the atom is predicted at 6.01 eV.