Fragmentation of C/sub 60/ and C/sub 70/ clusters and bulk C/sub 60/

Summary form only given. We have investigated the fragmentation of C/sub 60/, C/sub 70/ carbon clusters and bulk C/sub 60/ using molecular-dynamics simulation combining with the empirical-tight binding total-energy calculation method. The fragmentation process is studied by considering the heat capacity, binding energy, and the average number of neighboring atoms in terms of temperature. We found that the fragmentation of C/sub 60/ and C/sub 70/ starts from bond-breaking of single bond between hexagon and pentagon and later forms dimers, linearized chains. The fragmentation temperature is near 4000 K for both clusters. We then formed bulk (FCC) C/sub 60/ to see the structural changes in terms of temperature. The FCC structure is sustained up to 1000 K even though an individual C/sub 60/ cluster is distorted while rotating. The fragmentation process at high temperature will be further studied.