A new interpretation of the OH-stretch spectrum of ice

A new interpretation is presented of the vibrational band shapes of the pro ton disordered ice Ih and Ic in the OH and OD stretch region. The vibration ally excited states are shown to be related to those of a periodic system, whose unit cell is composed of four oscillating dipoles in a tetrahedral ar rangement around an O-atom. Analysis of the excitations in this periodic sy stem and of the perturbation induced by disorder is used to provide a detai led assignment of the band shapes of the measured spectra. (C) 1999 America n Institute of Physics. [0021-9606(99)00707-2].