Theoretical studies of the water-cluster anions containing the OH{e}HO structure: energies and harmonic frequencies

In addition to isomers having a dipole-bound electron, the internally bound electron isomers of trimer, tetramer and hexamer water anions are found using an ab initio molecular orbital method. The latter isomers have a characteristic OH{e}HO structure. The interaction between the excess electron {e} and the surrounding OH bonds holds the structure stable. The calculated vibrational infrared spectrum for a hexamer anion with two double proton-acceptor water molecules shows a qualitatively similar vibrational spectrum with the one observed. A strong correlation between the vertical detachment energy and the distribution of the excess electron is also found.