{Q(q)over-bar}{(Q)over-bar(('))q} molecular states

Masses for {Q (q) over bar}{(Q) over bar (('))q} molecular states are systematically studied in QCD sum rules. The interpolating currents representing the related molecular states are proposed. Technically, contributions of the operators up to dimension six are included in operator product expansion. Mass spectra for molecular states with {Q (q) over bar}{(Q) over bar (('))q} configurations are obtained.