  The formation of a hydroxylated native oxide layer on Si(001) under wet
conditions is studied by means of first principles molecular dynamics
simulations. Water molecules are found to adsorb and dissociate on the oxidised
surface leading to rupture of Si-O bonds and producing reactive sites for
attack by dissolved dioxygen or hydrogen peroxide molecules. Tensile strain is
found to enhance the driving force for the dissociative adsorption of water,
suggesting that similar reactions could be responsible for
environmentally-driven sub-critical crack propagation in silicon.
