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Figures I and 2 show, respectively, the structures of six isomers of C32 and 18 IPR isomers of C86 that have been included in our study. Each structure is endowed with point group symmetry index; the number in parenthesis enumerates species of the same symmetry. Each of the presented structures has been optimized using the SCC-DFTB method. Initial geometries were taken from Ref. 10. At the equilibrium geometries we perform analytical computation of Hessian that is used for obtaining harmonic vibrational frequencies. The vibrational eigenvectors obtained in that way are used subsequently for calculating derivatives of dipole moment and polarizability along the normal modes. Cartesian derivatives of dipole moment and polarizability are obtained using numerical differentiation with respect to the components of external electric field and analytical differentiation with respect to nuclear displacements. These quantities allow us for determining intensities in IR and Raman spectra. Figure 3 shows IR and Raman spectra obtained for six isomers of C32. All IR spectra use the same intensity scale. Similarly, all Raman spectra use the same intensity scale. To transform calculated Raman activities into quantities directly accessible in experiment, i.e. Raman intensities, we have followed Ref. II. It has been assumed that spectra have been recorded at temperature T=25° C and that the frequency of the exciting laser was 9398.50 cm·1. All calculated IR and all calculated Raman spectra look very differently for all investigated isomers of C32. This situation is quite understandable. C32 is a very small and very constrained fullerene. Small change in topology results in large changes in bond distances and bond angles of the optimized structures. Therefore, the resultant spectra look very different for all the considered isomers. The situation is quite different for C86. Figure 4 presents IR spectra of 18 various IPR isomers of C86 and Figure 5, corresponding Raman spectra. Most of the presented spectra look rather similar displaying similar features located at similar regions. The largest individual departure from the general trend can be observed for the D 3 isomer of C86 both for IR and Raman spectra and the C2v (I) isomer for IR spectra. This isomer has relatively high symmetry that does not permit many vibrational normal modes to be active in either IR or Raman spectrum. Summarizing, we can say that the overall similarity of the reproduced spectra is much larger for the isomers of C86 than for those of C32.