Molecular dynamics simulations of nanocarbons at high pressure and temperature

A molecular dynamics study of carbon nanoparticles; (980 and 10,034 atoms) under high temperature (1000-7000 K) and high pressure (2-45 GPa) has been made using the reactive LCBOPII potential. The most stable structure of the small cluster is onion-like (encapsulated fullerenic) on the whole pressure range, whereas a transition from onion-like to nanodiamond is observed for the big cluster as pressure increases from 2 to 45 GPa. The melting mechanism depends on the structure, initiated in the core in the case of an onion cluster and at the surface for the nanodiamond. A schematic phase diagram is proposed, that takes into account the finite size effects. (c) 2009 Elsevier Ltd. All rights reserved.