On the vibrational modes of C-60

The vibrational spectrum of C-60 is compared to the spectrum of a classical isotropic elastic spherical shell. We show correlations between the low frequency modes of C-60 and those of the spherical shell. We find the spherical model gives the approximate frequency ordering for the low frequency modes. We estimate a Poisson ratio of sigma approximate to 0.30 and a transverse speed of sound of v(s) approximate to 1800 m/s for the equivalent elastic shell. We also find that omega(M(1))/omega(M(0)) = root 3/2 for the shell modes M(0) and M(1), independent of elastic constants. We find that this ratio compares favorably with an experimental value of 1.17.