Molecular dynamics study of the fragmentation of silicon-doped fullerenes

CHU-CHUN FU; JAVIER FAVA; RUBEN WEHT; M. WEISSMANN

PHYSICAL REVIEW B

AMER PHYSICAL SOC

Año: 2002 vol. 66 p. 54051 - 54058

1098-0121

Tight-binding molecular dynamics simulations, with a nonorthogonal basis set, are performed to study the fragmentation of carbon fullerenes doped with up to six silicon atoms. Both substitutional and adsorbed cases are considered. The fragmentation process is simulated starting from the equilibrium configuration in each case and imposing a high initial temperature to the atoms. Kinetic energy quickly converts into potential energy, so that the system oscillates for some picoseconds and eventually breaks up. The most probable first event for substituted fullerenes is the ejection of a C2 molecule, another very frequent event being that one Si atom goes to an adsorbed position. Adsorbed Si clusters tend to desorb as a whole when they have four or more atoms, while the smaller ones tend to dissociate and sometimes interchange positions with the C atoms. These results are compared with experimental information from mass abundance spectroscopy and the products of photofragmentation