Rietveld ESD on Unit cell parameter vs the standard deviation from multiple packings and measurements
- Rietveld ESD on the “a” unit-cell parameter: 0.00008
- Standard Deviation on the “a” unit-cell parameter: 0.00008
- Standard deviation from multiple measurements is not significantly different from the estimated standard deviation (ESD) of a single measurement
- However, you can still get problems with accuracy due to misalignment in different powder diffractometers.
- Two theta offset should be a constant of the diffractometer
- Sample displacement should vary with each inserted sample
- Never refine both two-theta and sample displacement