Water heptamer with an excess electron: Ab initio study

The electron–water heptamer is one of the “magic” numbers in the mass spectra of electron–water clusters, but up to now the structure of the electron–water heptamer is not known. Thus we have investigated a number of low-energy structures, and report the lowest-energy structure using ab initio calculations. The relative energies, vertical electron-detachment energies, and OH vibrational frequencies of several lowest energy conformers are discussed. As in the case of e−(H2O)6, the electron affinity for e−(H2O)7 is predicted to be positive, which would explain the intense peak observed in the time-of-flight mass spectra.