We present a computational study of the structure and dynamics of an excess
electron in a medium-sized water cluster aimed at addressing the question of interior vs.
exterior solvation. Ab initio Born-Oppenheimer molecular dynamics simulations are
performed within the DFT framework, employing a hybrid Gaussian and plane waves formalism 
together with the PBE exchange-correlation functional and norm-conserving
pseudopotentials. The analysis of a 15 ps trajectory allows us to reach the following
conclusions: (i) the excess electron is predominantly located at the cluster surface
(even if it is initially placed in the interior), (ii) the computed electron binding energies
correlate with the electron localization rather than with its bulk vs surface location, (iii)
a dynamical interconversion between two different H-bond patterns around the electron
is found. The computed electron binding energies and the most relevant features of
the IR spectrum are in a very good agreement with previous experimental studies.