RAMAN AND INFRARED-SPECTRA OF HEXAGONAL ICE BETWEEN 0 AND 400 CM-1 - A MOLECULAR-DYNAMICS SIMULATION

We use the experimental values of the polarizabilities of the water mo lecule in conjunction with atomic trajectories obtained from molecular dynamics (MD) simulations to calculate numerically the Raman and infr ared (IR) spectra for hexagonal ice. We compare the results when the M D trajectories are generated using an effective two-body potential and a polarizable ab-initio potential. We find that, for both potentials, the IR and the Raman spectra, in the region between 0 and 400 cm-1, a re dominated by induced dipole contributions. The polarizable ab-initi o potential reproduces fairly well the experimental spectra, while the results for the two-body empirical potential are less satisfactory.