Structural and vibrational properties Of C36 and its oligomers (C36)M=2,3,4 by tight-binding molecular dynamics

Non-orthogonal tight-binding molecular-dynamics is employed to calculate structural and vibrational properties of C-36 and its oligomers (C-36)(M=2,3,4). The lowest energy configuration of the C-36 cage is confirmed to have D-6h symmetry. For the dimer, too, the D-2h structure reported in the literature is found. The vibrational spectrum is identified with the power spectrum of the displacement autocorrelation function. Additional vibrational properties are extracted from the dynamical matrix. For the monomer, fair agreement with available ab initio calculations is achieved, with comparatively smaller deviations in the Raman-frequencies than for published semi-empirical calculations. The features of the vibrational modes are correlated with the structural properties of the oligomers.