Coexistence of bucky diamond with nanodiamond and fullerene carbon phases

The transformation of nanodiamonds into carbon onions, and vice versa, has lead to the introduction of a new intermediate phase of carbon, coined ``bucky diamond,'' with a diamond core encased in an onion-like shell. Using a model based on the atomic heat of formation to describe the phase stability of carbon nanoparticles, we have calculated the relative stability of bucky diamonds and carbon onions for comparison with previous results for nanodiamond and fullerenes. Our results show that bucky diamond occupies a coexistence region, spanning the calculated upper limit of fullerene stability and the lower limit of nanodiamond stability.