Structure, stability, and vibrational properties of polymerizedC60

We have applied a density-functional based nonorthogonal tight-binding (DF-TB) method to study the structure, energetics, and vibrational properties of five different [${\mathrm{C}}_{60}$ ${]}_{\mathit{N}}$ oligomers (N=2, 3, and 4). In order to compare our results with the experimental spectra, Raman intensities have been calculated for each cluster using the bond polarization model. To address the energetics associated with polymer stability, we have calculated the DF-TB reaction barrier for the dissociation of the ${\mathrm{C}}_{60}$ dimer along two different paths. The cohesive energy and the Raman-active interball mode of the ${\mathrm{C}}_{60}$ dimer have been investigated with an all-electron, self-consistent density-functional based method also.