Abstract
The stability of Ne@C
60
and He@C
60
is discussed in the context of a spherical model where the carbon atoms are smeared out into a uniform shell. The electronic properties of the sixty
π
electrons together with those of the central atom are treated in the Thomas-Fermi approximation. Simple electrostatic reasoning elucidates the nature of the radial stability of the complex. A method to include non-spherical corrections is outlined. Possible bonding topologies of the central atom and the C
60
cage are discussed, as well as the relevance of these topologies to incipient central atom distortions.