THE INTERACTION OF HYDROGEN WITH C-60 FULLERENES

Experiments and molecular dynamics (MD) simulations of low-energy (10- 30 eV) H interactions with the C60 molecule have been carried out in o rder to investigate the possible chemical combinations at these energi es. It is found that the preferred minimum-energy state is for the H a tom to be attached to the outside of the molecule but that some trappi ng of the H atom within the cage should be possible if the C60 molecul e has only a small initial energy. As the excitation of the molecule i ncreases, trapping becomes less likely. The trajectories calculated by MD show a number of different interactions: (i) reflection of the H a tom, (ii) transmission of the H atom through the structure, (iii) impl antation within the molecule, (iv) attachment of the H atom to the out side of the structure and (v) initial implantation and attachment of t he H atom to the inside of the structure followed by bond-breaking of the C atoms and final attachment of the H atom externally. The experim ental results of the interaction process with 'energetic' C60 molecule s so far have shown no evidence of the existence of a trapped H atom a t the centre of the C60 cage, but indicate strong evidence for externa lly bonded H atoms.