Accession Number : AD0765344

Title :   Interionic Vibrations and Glass Transitions in Ionic Oxide Metaphosphate Glasses.

Descriptive Note : Technical rept.,

Corporate Author : BROWN UNIV PROVIDENCE R I DEPT OF CHEMISTRY

Personal Author(s) : Exarhos,Gregory J. ; Miller,Philip J. ; Risen,William M. , Jr

Report Date : 13 AUG 1973

Pagination or Media Count : 43

Abstract : The far infrared spectrum of each ionic metal-metaphosphate glass, (MPO3)n (M = Li, Na, K, Rb, Cs) and (M(PO3)2)n (M = Ca, Sr, Ba), contains a broad absorption band whose peak frequency and halfbandwidth are strongly dependent on the mass and charge of the glass-modifying cation. Each such band, which appears as the envelope of the optical phonon spectrum of the crystalline form of the material, is assigned to a density of coupled oscillator pseudo phonon states, which assignment is shown to be consistent with experimental linear variations of frequency with bandwidth. The net effect of coupling the oscillators in the vitreous (disordered) system is equivalently treated as a single damped harmonic oscillator. The damping coefficient is constant in each series as is the complex part of the refractive index. The force constant, the excitation quantum number, and mean square amplitudes are computed. It is shown that the energy required to pull the anion site away from the cation, permitting the glass transition to ensue, is a constant for each series of metaphosphate glasses.

Descriptors :   (*PHOSPHATE GLASS, *INFRARED SPECTRA), (*PHONONS, PHOSPHATE GLASS), TRANSPORT PROPERTIES, CRYSTAL STRUCTURE, BANDWIDTH, RAMAN SPECTROSCOPY

Subject Categories : Atomic and Molecular Physics and Spectroscopy
      Solid State Physics

Distribution Statement : APPROVED FOR PUBLIC RELEASE