structural properties referring to length scales beyond the basic tetrahedral unit. We
generate a model structure that yields a neutron structure factor in accord with experiment.
The inelastic-neutron, the infrared, and the Raman spectra, calculated within a density-
functional approach, also agree with respective experimental spectra. The accord for the
Raman spectrum supports a Ge-O-Ge angle distribution centered at 135°. The Raman …