Electron density distribution in endohedral complexes of fullerene C₆₀, calculated based on the Gauss law.

This study demonstrates that different partial charge methodologies, consisting of an attribution of the total electron density to particular atoms of a molecule, generate very divergent results in the case of atoms doped into a fullerene cage. A new method of calculating the density distribution inside and outside fullerene complexes has been proposed and applied in the case of C₆₀, [F@C₆₀]⁻, [Na@C₆₀]⁺, and He@C₆₀. It allowed for the calculation of the electron density between surfaces, isomorphic with the C₆₀ cage, lying inside and outside the latter, as well as the charge in the space surrounding the central atom (or the central point in the case of empty C₆₀).