Knowledge Bank

It has often been suggested that gas-phase $(H2O)n-$ clusters ought to exist, and that some might be counterparts to solvated (hydrated) electrons. Recently, these entities were observed in the gas-phase by Haberland et al. Here, we report the first spectroscopic study of the gas-phase negative cluster ions, ($H2O)n-$. Using 2.409 eV photons, we have recorded the negative ion photoelectron (photodetachment) spectra of ($H2O)n=11-15,19-$. These spectra consist of single broadened peaks each of which are shifted to successively higher electron binding energies with increasing cluster size. The implications of these results regarding the nature of ($H2O)n-$ will be discussed.