STRUCTURE OF THE VIBRATIONAL SPECTRUM AND THE SELECTION RULES IN THE HYPER-RAMAN AND RAMAN SPECTRA OF LIGHT SCATTER IN INORGANIC GLASSES.

In glasses the vibrational excitations (polaritons and purely mechanical vibrations) are characterized by a specific wave vector. In the vibrational spectra of glasses, the alternative prohibition is valid; the dipole vibrations in the Raman scatter are forbidden. This prohibition is strict since it is produced by the macroscopic symmetry of the glass. A new approach to the interpretation of vibrational spectra in glasses is proposed.