Small-angle X-ray scattering study of glassy GeO₂

Abstract

A small-angle X-ray scattering study of glassy GeO2 is reported. Data were obtained from 4π sinθ/λ = 0.05 to 2.0 using a Kratky camera. The SAXS intensity decreased monotonically with decreasing angle from the main diffraction peak, and was not noticeably changed by hydrofluoric acid surface treatment or various annealing treatments. The intensity scattered at the smallest angle was 49±2.5 e.u. molec−1. Extrapolated to zero angle, the intensity corresponds to root-mean-square density fluctuations of 10−12 V−1/2 cm−3/2, a value close to that expected from the thermodynamic fluctuation theory of liquids. A parallel study of fused silica has indicated mean-square density fluctuations similar to those found in GeO2. The results are taken as evidence contrary to representations of structure based on specific arrays differing significantly from the interconnecting material.