  We apply a version of the recently developed approach combining the
correlation potential, linearized singles-doubles coupled-cluster, and the
configuration interaction methods to the spectra of the heavy alkaline earths
barium, radium, and element 120. Quantum electrodynamics radiative corrections
are included. We have found unprecedented agreement between ab initio theory
and experiment for the spectra of barium and radium, and we make accurate
predictions for missing and unreliable data for all three atoms.
