Calculations of the spectra of superheavy elements E119 and E120+

High-precision calculations of the energy levels of the superheavy elements E119 and E120+ are presented. Dominating correlation corrections beyond relativistic Hartree-Fock are included to all orders in the Coulomb interaction using the Feynman diagram technique and the correlation potential method. The Breit interaction and quantum electrodynamics radiative corrections are considered. Also, the volume isotope shift is determined. A similar treatment for Cs, Fr, Ba+ and Ra+ is used to gauge the accuracy of the calculations and to refine the ab initio results.