The hydrated electron is a crucial species in radiative processes, and it
has been speculated that its behavior at the water surface could lead to specific interfacial
chemical properties. Here, we address fundamental questions concerning the structure
and energetics of an electron at the surface of water. We use the method of ab initio
molecular dynamics, which was shown to provide a faithful description of solvated
electrons in large water clusters and in bulk water. The present results clearly
demonstrate that the surface electron is mostly buried in the interfacial water layer, with
only about 10 % of its density protruding into the vapor phase. Consequently, it has a
structure that is very similar to that of an electron solvated in the aqueous bulk. This
points to a general feature of charges at the surface of water, namely, that they do not
behave as half-dehydrated but rather as almost fully hydrated species.