Total electronic energy by tight binding approximation and experimental   toughness of three different hybrid polymers
  We computed by a modified tight binding approximation, the total electronic energy of three different hybrid polymers: $H-SiO_2$, $CH_3-SiO_2$ and $C_6H_5-SiO_2$. We made the hypothesis that the structures of these polymers are amorphous. Computational results regarding the total electronic energy and experimental data \cite{ferchichi} on the toughness of these three hybrid polymers were compared. A good qualitative agreement was found between computations and experiments. 
N.Olivi-Tran, A.Ferchichi, S.Calas, P.Etienne