Molecular dynamics study of the fragmentation of silicon doped fullerenes

TL;DR

This study uses molecular dynamics simulations to investigate how silicon-doped fullerenes fragment, revealing specific ejection patterns and behaviors of silicon clusters, with results aligning with experimental observations.

Contribution

It provides new insights into the fragmentation mechanisms of silicon-doped fullerenes using detailed molecular dynamics simulations.

Findings

C2 molecule ejection is the most common initial event.

Silicon clusters with four or more atoms tend to desorb as a whole.

Smaller silicon clusters often dissociate and interchange with carbon atoms.

Abstract

Tight binding molecular dynamics simulations, with a non orthogonal 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.