ENERGETICS OF MULTILAYERED CARBON TUBULES

We study the structure of nested multilayered systems composed of two infinite carbon tubules via density functional theory. The calculated intertubule distance is 3.39 angstrom, comparable to the recent measurement of 3.4 angstrom. In such a system, the energy gained by adding a new cylindrical layer around a central one is estimated to be 80% of the graphite dilayer binding energy. Low translation and rotation barriers suggest that carbon tubules of limited length could easily slide into or out of each other and rotate along the cylindrical axis. Comparison with graphite and hyperfullerenes is proposed.