AB-INITIO MOLECULAR-DYNAMICS OF C-70 - INTRAMOLECULAR VIBRATIONS AND ZERO-POINT MOTION EFFECTS

We present an ab initio calculation of the vibrational properties of C70 based on a Car-Parrinello simulation at low temperature and a self-consistent analysis of the atomic trajectories. We compare our results with inelastic neutron scattering and, whenever possible, with infrared and Raman measurements. Excellent agreement is found with neutron scattering data both for structural and vibrational properties. We find that the atomic displacement due to the zero-point motion is of the same order as the width of the bond-length distribution. Comments are made on several structural determinations and on model calculations.