Rotationally resolved dicopper laser-induced fluorescence spectra and the long-awaited Π state

The analogy between copper and hydrogen atoms (single s-shell valence electron) has made dicopper (Cu2 ) the model diatomic molecule for studies of transition metal bonding. Results of a study of the excited states, on which there has been little data, are reported. The known excited states (A and B) have been shown to have Σ symmetry, and the recently discovered C state has been shown to have Π symmetry. Results on J 2R X bands and G 2R X bands are also reported.