Abs(raeL An interatomic potential for arbon is developed Ihal is kmed on an empirical tighl-binding approach. The model repmduces aocuraleiy the energyversus-volume diagram of arbon polyiypes and gives a good description of Ihe phonons and elastic mnslanls for carbon in the diamond and graphite structures. To test the transferability of the model to differen1 atomic environments further, w performed moleculardpamics simulations to study the liquid phase and lhe pmpenies of mall arbon micmdus ters. The rerults obtained are in good agreement wilh those obtained from ob bzitio calculations.

Combining an efficient simulated annealing scheme for generating closed, hollow, spheroidal cage structures with a tight-binding molecular-dynamics method for energy optimization, the ground-state structure of every even-numbered carbon fullerene from C72 to C102 is determined. As a general trend, most ground-state structures of the large fullerenes have relatively low symmetries. In many cases, several isomers of a fullerene are found to have competitively low energies, which suggests that a mixture of these isomers can be observed in experimental prepared samples.

The ground-state structures of small fullerenes below C70 were determined by tight-binding molecular-dynamics total energy optimization. An efficient simulated annealing scheme was used to generate closed, hollow, spheroidal cage structures for all even-numbered carbon clusters from C20 to C70. As a general trend, fullerenes prefer geometries which separate the pentagonal rings as far apart as possible. Except for C60, C70, and C50, most fullerenes have relatively low symmetries.

No abstract