+The tetrahedral and the <110> dumbbell self interstitial configurations can be reproduced as observed in \ref{}.
+The formation energies are $3.4\, eV$ and $4.4\, eV$ respectively.
+However the hexagonal one is not stable opposed to what is presented in \ref{}.
+The atom moves towards a energetically more favorable position very close to the tetrahedral one but slightly displaced along the three coordinate axes.
+The formation energy of $4.0\, eV$ of this type of interstitial equals the result obtained in the reference for the hexagonal one.
+The same type of interstitial is observed within the random insertion runs.
+Variations exist where the displacement is along two axes ($E_f=3.8\, eV$) or along one axis ($E_f=3.6\, eV$) succesively approximating the tetrahedral configuration and formation energy.
+
+The tetrahedral and <110> dumbbel carbon interstitial configurations are stable.
+The formation energies are $2.7\, eV$ and $1.8\, eV$ respectively.
+Again the hexagonal one is found to be not stable.
+The interstitial atom moves to the more favorable <100> dumbbell position, which has a formation energy of $0.5\, eV$.
+There is experimental evidence \ref{} of the existence of this configuration.
+This type of configuration is frequently observed for the random insertion runs.
+
+
+