  High-precision calculations of the energy levels of the superheavy element
Z=120 are presented. The relativistic Hartree-Fock and configuration
interaction techniques are employed. The correlations between core and valence
electrons are treated by means of the correlation potential method and
many-body perturbation theory. Similar calculations for barium and radium are
used to gauge the accuracy of the calculations and to improve the ab initio
results.
