Unimolecular Decay of Metastable Cluster Anions: (O 2 ) N − * → (O 2 ) N‐1 − + O 2

Unimolecular dissociation of metastable excited states of (O 2 ) n − * into (O 2 )   n‐1 −cluster anions has been detected and studied quantitatively for n in the range of 13 to 22. The apparent metastable (decay rates determined increase with cluster size in from ∼ 5000 s −1 (for n = 13) up to ∼ 8500 s −1 for n = 22).