RESULTS OF THE FIRST STAGE OF CALCULATIONS
A single irradiated atom leads to a split interstitial defect.
- We discovered this defect in the computer sample
with visualization techniques - we highlighted the expected bond angles
and it just jumped out of the 5120 atom sample.
Previous ab initio studies had shown this to be the most stable
defect, no-one knew how it developed.
- Using colorcoding to highlight the three-fold coordinated atoms,
we found substantial relaxation into these atoms near the place where one
atom was displaced. The extent of this was a surprise.
- More bombarding atoms make a mess, but on subsequent annealing
(heating and slow cooling) small regions of graphitic planes develop.
These will percolate when of sufficient density.
- The big question with this type of calculation is whether the classical
potentials are adequate to model transformations between sp2 and sp3 bonded
carbon: we made special tests of this and reproduced ab initio
calculations of the process of graphitization of Diamond.