DENSITY-FUNCTIONAL STUDY OF THE INTERSHELL INTERACTION ENERGY IN CARBON ONIONS

The intershell interaction energy in carbon onions is self-consistently obtained by using the local density approximation for the pi electrons in a spherically averaged pseudopotential. Onions formed by two, three, and four shells with up to 1800 atoms are considered. Our results agree well with recent large-scale ab initio calculations and with experimental evidence that onions are more stable than are single fullerenes for cluster sizes larger than 100 atoms. The small electronic redistribution that takes place when onions are formed supports the picture of weak van der Waals forces between single fullerenes. (C) 1995 John Wiley & Sons, Inc.