Polymerization and depolymerization of fullerenes induced by hole injection from scanning tunneling microscope tips

Reversible polymerization and depolymerization reactions of fullerene (C60) molecules are induced by tunnel injection of holes from tips of scanning tunneling microscopes similarly to the reactions induced by tunneling electrons. The bi-directional and bi-polar features of the hole-induced and electron-induced reactions can be interpreted by a unified model considering ionic reactions over symmetry-imposed barriers in the [2+2] cyclo-addition and the reverse reactions.