Fig. 3. (I) Graphical models illustration of relaxed geometry of six metal ions in relation to the fullerenes. (a) Configuration with six metal ions positioned inside the fullerene cage and (b) configuration with six metal ions positioned outside the fullerene cage. Theoretical Raman spectra for (II) C₆₀-Cl, (III) Ag ions outside the cage Ag-C₆₀-Cl, (IV) Ag ions inside the cage Ag-C₆₀-Cl, (V) Cu ions outside the cage Cu-C₆₀-Cl, and (VI) Cu ions inside the cage Cu-C₆₀-Cl. The spectral peak alignment is further corroborated by the matching peaks in the experimental spectra (Fig. 2).