Vibrational spectroscopy of cation-site interactions in phosphate glasses

Thirty different binary metal oxide glasses having the metaphosphate composition have been prepared containing cations from the following groups: alkali metals, alkaline earths, transition metals, and lanthanide and actinide metals. Far infrared absorption assigned to the cation vibration in its oxygen cage has been measured for these glasses. Empirical ionic models are proposed correlating the absorption maximum with the cation mass, charge, and ionic radius. Discrepancies between the observed and predicted vibrational frequency indicate a more covalent interaction between the metal cation and the glass network. Raman intensities and vibrational frequencies of the network metaphosphate vibrations have been obtained and provide additional evidence about the cation–site interaction.