Influence of packing on the vibrations of homogeneous bundles of C60 peapods

• The Raman-active modes in bundles of linear and zigzag C60 peapod are calculated.
• We focus on the C60 filling factor, bundle size and nanotube structure effects.
• The breathing mode region is strongly affected by tube–tube and tube–C60 interactions.
• We show a radial mode splitting when the C60 filling factor inside the tube increases.
• The calculated results are compared with the experimental Raman data.

The non-resonant Raman spectra of homogeneous bundles of C60 peapods (C60 inserted in single-walled carbon nanotubes) are calculated in the framework of spectral moment method, together with a bond-polarizability model. The evolutions of the low wavenumber range of the Raman spectrum of homogeneous bundles of C60 peapods as a function of the nanotube diameter and the size of bundles are discussed. The effect of the C60 filling factor is investigated in detail. The results are compared to experimental Raman data measured on various samples of C60 peapods.