Abstract: | Interface water anions composed of several chainlike or cyclic fragments were simulated with a 6‐31++G** basis set at the unrestricted Hartree–Fock level with the second‐order Moeller–Plesset perturbation theory corrections taken into account. The estimated vertical electron detachment energies (VDEs) of (H2O) anions were approximated by a VDE‐n?1/3 dependence close to the experimental one. A hypothesis about the predominant formation of interface structures under conditions of molecular flows is put forward. The atomic population analysis, character of the highest occupied molecular orbital, and changes in the geometry of interface anions with an increase in their molecular size reveal the compact localization of the excess electron density in water clusters and allow evaluating the effective excess‐electron radius of condensed water as 2.5 Å, in good agreement with a similar empirical estimate. The scope of the data obtained shows the relatively low probability of the formation of octahedral hydration shells compared to the tetrahedral coordination of solvating water molecules. © 2002 Wiley Periodicals, Inc. Int J Quantum Chem, 2002 |