What information can be obtained from amorphous samples?
For amorphous samples, we can provide comprehensive structural characterization through total scattering measurements combined with pair distribution function (TS-PDF) analysis. This technique is particularly valuable for materials lacking long-range order. The information you can obtain includes:
- Local atomic structure: Identification of short-range ordering and coordination environments around atoms
- Bond distances: Precise measurements of interatomic distances between nearest neighbors
- Coordination numbers: Determination of how many atoms surround each atom at specific distances. Note that this requires absolute scaling of the data, which requires additional normalization steps.
- Medium-range order: Structural correlations extending beyond nearest neighbors (typically in the range of approximately 10–30 Å)
- Structural domains: Detection of nano-domains or local ordering
- Phase identification: Determination if the sample is truly amorphous or contains nanocrystalline domains
- Structural evolution: When measurement are performed on samples that have undergone different synthesis or processing procedures, insights into relative structural changes can be determined
- Quantitative modeling: The data can be used for real space structure refinement such as small-box modeling, Reverse Monte Carlo modeling or other computational approaches to generate 3D structural models
- Composition-structure relationships: When comparing related compositions, understanding how composition affects local structure
- Density information: Indirect information about atomic density and microporosity