화학공학소재연구정보센터
Journal of Chemical Physics, Vol.108, No.6, 2631-2637, 1998
Disordered and ordered C-28 solids
Using tight-binding molecular dynamics, we have performed computer experiments to mimic the gas phase growth of a disordered solid composed of C-28 fullerenes. The growth has been simulated by repeated low energy collisions of molecules coming from random directions. The resulting solid is composed of undamaged C-28 cages, with most fullerenes being three-and four-fold coordinated, similar to C atoms in amorphous materials. The system contains a high percentage of distorted sp(2) C sites and only a small proportion of sp(3) sites. These results help clarify the structure of disordered films obtained experimentally by small fullerene deposition on surfaces. Furthermore, we have compared the properties of the disordered C-28 solid (a-C-28) With those of ordered C-28 solids. We have found that the energy of a-C-28 is close to that of hyperdiamond (0.1 eV/atom higher) and differs by a few meV from that of other ordered structures, such as 2D-hypergraphite, hexagonal and clathrate solids. This indicates that in condensed phases C-28 molecules can act as carbon superatoms, while showing more bonding flexibility than C atoms; in particular the capability of acting as six-fold coordinated building blocks of hexagonal solids, which are as stable as a-C-28.