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Previously, we reported an electron-water pseudopotential designed to be used in conjunction with a polarizable water model, in order to describe the hydrated electron [L. D. Jacobson et al., J. Chem. Phys. 130, 124115 (2009)]. Subsequently, we found this model to be inadequate for the aqueous electron in bulk water, and here we report a reparametrization of the model. Unlike the previous model, the current version is not fit directly to any observables; rather, we use an ab initio exchange-correlation potential, along with a repulsive potential that is fit to reproduce the density maximum of the excess electron's wave function within the static-exchange approximation. The new parametrization performs at least as well as the previous model, as compared to ab initio benchmarks for (H2O)n- clusters, and also predicts reasonable values for the diffusion coefficient, radius of gyration, and absorption maximum of the bulk species. The new model predicts a vertical electron binding energy of 3.7 eV in bulk water, which is 1.4 eV smaller than the value obtained using nonpolarizable models; the difference represents the solvent's electronic reorganization energy following electron detachment. We find that the electron's first solvation shell is quite loose, which may be responsible for the electron's large, positive entropy of hydration. Many-body polarization alters the electronic absorption line shape in a qualitative way, giving rise to a high-energy tail that is observed experimentally but is absent in previous simulations. In our model, this feature arises from spatially diffuse excited states that are bound only by electronic reorganization (i.e., solvent polarization) following electronic excitation. [ABSTRACT FROM AUTHOR]

The prevailing structural paradigm for the aqueous electron is that of an s-like ground-state wave function that inhabits a quasi-spherical solvent cavity, a viewpoint that is supported by numerous atomistic simulations using various one-electron pseudopotential models. This conceptual picture has recently been challenged, however, on the basis of results obtained from a new electron-water pseudopotential model that predicts a more deiocalized wave function and no well-defined solvent cavity. Here, we examine this new model in comparison to two alternative, cavity-forming pseudopotential models. We find that the cavity-forming models are far more consistent with the experimental data for the electron's radius of gyration, optical absorption spectrum, and vertical electron binding energy. Calculations of the absorption spectrum using time-dependent density functional theory are in quantitative or semiquantitative agreement with experiment when the solvent geometries are obtained from the cavity-forming pseudopotential models, but differ markedly from experiment when geometries that do not form a cavity are used. [ABSTRACT FROM AUTHOR]

The electronic absorption spectrum of the aqueous electron in bulk water has been simulated using long-range-corrected time-dependent density functional theory as well as mixed quantum/classical molecular dynamics based on a one-electron model in which electron-water polarization is treated self-consistently. Both methodologies suggest that the high-energy Lorentzian tail that is observed experimentally arises mostly from delocalized bound-state excitations of the electron rather than bound-to-continuum excitations, as is usually assumed. Excited states in the blue tail are bound only by polarization of the solvent electron density. These findings have potentially important ramifications for understanding electron localization in polar condensed media as well as biological radiation damage arising from dissociative electron attachment. [ABSTRACT FROM AUTHOR]