Low temperature photoelectron spectra of water cluster anions

Photoelectron spectra of cold (10K) size selected water cluster anions (H(2)O)(n)(-) and (D2O)(n)(-) have been measured in the size range n = 20-120. A new isomer with a higher binding energy than the so-called isomer I has been identified, which appears in the size range n = 25-30 and for (H(2)O)(n)(-) becomes dominant at n = 46. Magic numbers observed in the mass spectra of the cluster anions provide evidence that this new isomer class consists of clusters with an internal electron. (C) 2009 American Institute of Physics. [doi:10.1063/1.3245859]