In set (2), the target states have either one electron or one hole in two degenerate orbitals (π or E). To achieve a balanced treatment of the corresponding configurations, we used EOM-IP-CCSD to remove an electron from degenerate orbitals of a closed-shell reference to describe diatomic cations (Figure ) and EOM-EA-CCSD to add an electron to an empty degenerate orbitals of a cationic reference to describe calcium derivatives (Figure ).