The microscopic transport processes of an excess electron in bulk water are
studied using hybrid ab initio molecular dynamics calculations. In contras
t to the typical cavity obtained with solvated anions, the electron cavity
structure is found to be much more variable, with water molecules easily ex
changing at the surface of the cavity. The microscopic mechanism of electro
n transport involves a novel sequence of opportunistic electron redistribut
ions driven by a positive feedback between thermal fluctuations and the att
raction of the electron to hydrogen atoms that are not saturated in hydroge
n bonding. (C) 2001 Elsevier Science B.V. All rights reserved.