Decay processes of the C2 2Π1/2u states of Ar2+, Kr2+, and Xe2+

The threshold photoelectron photoion coincidence spectra of the rare gas dimers Ar2, Kr2, and Xe2 have been measured in the photon energy region between the first and second dissociation limits of the dimer ions. It has been found that the C2 2Π1/2u states of Kr2+ and Xe2+ completely dissociate via an optical transition to the repulsive B2 2Π1/2g state, while that of Ar2+ does not dissociate.