On the mechanism of formation of fullerenes and carbon nanotubes

Abstract

A possible mechanism of the formation of fullerenes and carbon nanotubes is proposed that is based on the notion of the strongly correlated state of π electrons in these materials (as well as in graphene layers). The presence of this state, in which the π electron densities on both sides of the carbon framework tend to be equal, decreases the energy of the system and stabilizes the carbon structure modifications under consideration. It is suggested that the graphene layer fragments considered as the initial material are polarized under the action of positive ions of inert gases or transition metals. This polarization leads to a redistribution of π electrons between the two sides of the initially planar graphene layer, which violates the equality of electron densities. As a result, the layer exhibits bending, which leads to the restoration of this equality. Under conditions of the strongly correlated π electron state, polarization not only modifies the state of hybridization of the polarized carbon atoms, but also leads to the formation of localized singlet pairs of π electrons (localized π-bonds). These changes maintain and additionally stabilize the curved structure upon termination of the polarizing action.