Solvation-induced cluster anion core switching from NNO 2- (N2 O) n-1 to O- (N2 O) n

We report a photoelectron imaging study of the [O (N2 O) n] -, 0n9, cluster anions generated via electron bombardment of a pulsed supersonic expansion of pure N2 O gas. Depending on cluster size, the photoelectron image features and spectral trends, examined at 355 and 266 nm, give evidence of two dominant core-anion structures, corresponding to the NNO 2- (N2 O) n-1 and O- (N2 O) n cluster anions. In agreement with previous studies, the n=1 anion has a covalently bound (Y -shaped) NNO 2- structure. The NNO 2- core is also found to persist in the larger clusters, up to n=3. However, for n4 (and up to at least n=9) signatures of an O- core are predominantly observed. Photofragmentation studies at 355 nm support these results.