https://doi.org/10.1351/goldbook.14232
Ratio of the statistical fluctuation \(\Delta a_{ik}\) of a lattice vector \(a_{i}\) along the direction \(a_{k}\) \[g_{ik} = \frac{\Delta a_{ik}}{a_{k}}\]
Notes:
- Values of \(g\) range from \(\pu{0}\) (distortion-free crystal) to \(\pu{0.03}\) (typical bulk polymer), to \(\pu{0.12}\) (\(\ce{SiO2}\) glass) to \(\pu{1}\) (Boltzmann gas).
- \(g\) can be determined from measurements of the integral breadth of successive orders of Bragg reflections [18b].