Vibrational predissociation spectra of the [formula omitted], n = 3–10, 12 clusters: Even–odd alternation in the core ion

Abstract

We report vibrational predissociation spectra of the O n − , n = 3–10, 12 cluster ions in the 700–2400 cm −1 range. The odd numbered clusters are consistent with their identification as O 3 − ⋅ ( O 2 ) n . The even numbered clusters are based on the O 4 − core ion, where the first two O 2 molecules add to O 4 − in locations that individually break the symmetry of the core ion, but together restore this symmetry. Beyond O 4 − ⋅ ( O 2 ) 2 , subsequent O 2 attachment yields bands close to that of neutral O 2, indicating that the special character of the O 4 − ⋅ ( O 2 ) 2 cluster is retained.