Hydrated electron: Nonempirical modeling

Water cluster anions (H2O)(n)(-) with n = 2 to 8 were analyzed as a prototy pe of a hydrated electron. Two types of structures were obtained by geometr y optimization in the unrestricted Hartree-Fock approximation. An excess el ectron could be localized either by a single water cluster or by two confro nting clusters with no H-bond between them. The vertical energies of electr on detachment from the anions estimated at the level of Moller-Plesset seco nd order perturbation theory were positive already at n less than or equal to 3. It was shown that eight water molecules were sufficient for the forma tion of the hydration sheath of an electron, because the most stable anion comprising two confronting chains was formed from the usual chain octamer s tructures. Terminal and interface types of excess electron density localiza tion were characterized.