  We have adapted classical molecular dynamics to study the structural and
dynamical properties of amorphous silica surfaces. Concerning the structure,
the density profile exhibits oscillations perpendicularly to the surface as
observed in liquid metal surfaces and the pair correlation functions as well as
the angle distributions show features (absent in the interior of the films)
that can be attributed to the presence of 2-fold rings which are perpendicular
to the surface. From the mean-squared displacement of the non bridging oxygen
atoms we find that in the interior region they move perpendicular to the
surface while they move parallel to it in the surface region.
