Polarizability as a tool to determine the electrostatic shielding effect of nanocarbon cages: a polarizability distribution study on noble gas endohedral fullerenes.

Shielding effects of a nanocage can be determined by the field felt by an encapsulated noble gas (NG) atom. Using the polarizability distributions about NG endohedral fullerenes (NGEFs), a new scheme based on the local polarizability of the NG is introduced to detect the shielding effects of fullerenes, using density functional theory calculations and Hirshfeld population analysis. For large cage sizes, this scheme can provide reliable results. Further analysis reveals that the shielding effect is dependent on the shape of the cage, and a shielding zone can be found around the center of the cavity in which the electric field can be considered to be uniform and of lower strength than that of an applied external field. For small cages, intermolecular interactions between the cage and the endoatom contribute to the overestimation of the shielding effects.