Abstract:
Neutron diffraction techniques have been employed to obtain an accurate high-resolution real space correlation function for vitreous GeO2. The GeO bond length is found to be 1.739 + and the rms bond length variation 0.048 angstrom. The distribution of intertetrahedral GeOGe angles is narrower than the equivalent distribution for vitreous SiO2, but the GeO angles within the basic tetrahedral GeO4 structural units appear to be more distorted - in line with a similar trend found for the corresponding alpha-quartz crystalline polymorphs. Structural (quasi-crystalline) models based on alpha-quartz and alpha-cristobalite GeO2 are rejected in that they fail to account for the continuous distribution of bond and torsion angles found in the glass.
