Simulation of Raman spectra of C60 and C70 by non-orthogonal tight-binding molecular dynamics

A non-orthogonal tight-binding molecular-dynamics formalism is used to simulate Raman spectra of the fullerene molecules C-60 and C-70 Two parametrization schemes for the Hamiltonian and the overlap matrix elements are investigated. The considered molecules are excited randomly and the Fourier transform of the displacement autocorrelation function is employed to extract the vibrational properties. Fair agreement with experiment and with force-constant and ab initio calculations is achieved, with comparatively smaller maximum errors in the frequencies than for other molecular dynamics or semi-empirical calculations from the literature.