Nucleation in amorphous carbon
under high pressure with diamond seed
Results of Lifshitz
66-atom diamond seed embedded into a random gaseous intial 512 cluster
in a 3.5 and 3 g/cc a-C matrix.
Then the structure was cooled from 8000 K, kept the seed frozen.
The growth of diamond is more efficient in the  direction in the
3.5 g/cc matrix and is less oriented for 3.0 g/cc matrix.
No growth was observed in a-C matrix of 2 g/cc.
Sample 141 at 3.9 g/cc
The pictures shows final configuration of
the initial sample
(78% ofsp3 bonds), and the samples heated to 40000 K
(83% ofsp3 bonds),
and to 50000 K (88 % ofsp3 bonds).
RDF and ADF
of the central sp3 cluster which
appears in the 50000 K sample are here.
At the process of heating after 1500 steps atoms reach the
stable configuration, and oscillate around their stable location.
(see here the mean square displasement
of atoms as a function of time). It's because of constrains from
the frozen diamond layers (in pure amorphous sample at high temperatures
samples are liquid).
At the densitis of and 3.6 and 3.7 g/cc the sample remains in the initial
configuration up to
temperature of heating 50000 K
Sample 171 at 3.7 g/cc
initial sample, 45% of sp3 bonds, 55% of sp2 bonds.