Task-focused Workflow

Detect and Fit XRD Peaks and Measure FWHM

Detect and fit diffraction peaks in NotyPlot. Review peak position, fitted FWHM and fit quality before using the values in further XRD calculations.

NotyPlot: Scientific Plotting & Peak Analysis XRD fit peaks
Start this workflow
InputAn XRD pattern containing resolvable diffraction peaks.
OutputReviewed peak positions, fitted FWHM values and a fitted pattern.

Workflow

  1. Import the XRD pattern, inspect background and detect the candidate peaks.
  2. Choose the fit model: automatic, Gaussian, Lorentzian or pseudo-Voigt according to the peak shape and analysis need.
  3. Fit the active peaks; overlapping fit windows are handled together when required.
  4. Inspect fitted curves, peak centers, FWHM values and any residual mismatch rather than accepting the parameters automatically.
  5. Exclude peaks whose overlap, asymmetry, truncation or poor sampling makes their width unreliable.
  6. Export or continue with only the reviewed fitted peaks needed for downstream XRD calculations.

What this workflow helps you do

Fit diffraction peaks to obtain reviewed peak positions and FWHM values rather than relying on a simple detected maximum. NotyPlot supports Gaussian, Lorentzian and pseudo-Voigt profile choices, including joint handling of overlapping fit windows.

Use this workflow when

  • Measuring fitted FWHM for XRD peaks.
  • Resolving nearby or partially overlapping diffraction features.
  • Preparing peak parameters for Scherrer, Williamson–Hall or other width-based analysis.

What you need before you start

  • An XRD pattern with suitable peak sampling and a reviewed background.
  • Candidate peaks that can be supported by the plotted signal.
  • Instrument and wavelength information when fitted widths will be used in downstream size/strain calculations.

Step-by-step workflow

  1. Import the XRD pattern, inspect background and detect the candidate peaks.
  2. Choose the fit model: automatic, Gaussian, Lorentzian or pseudo-Voigt according to the peak shape and analysis need.
  3. Fit the active peaks; overlapping fit windows are handled together when required.
  4. Inspect fitted curves, peak centers, FWHM values and any residual mismatch rather than accepting the parameters automatically.
  5. Exclude peaks whose overlap, asymmetry, truncation or poor sampling makes their width unreliable.
  6. Export or continue with only the reviewed fitted peaks needed for downstream XRD calculations.

What to review in the result

  • The fitted profile follows the measured peak across both flanks.
  • Overlapping peaks are represented plausibly rather than collapsed into one width.
  • The selected FWHM mode is clear for any downstream calculation.
  • Poorly fitted or truncated peaks are not used simply because a numeric result exists.

Before you report or export

  • Keep the chosen profile model and baseline state with the reported FWHM values.
  • Correct instrumental broadening before interpreting physical broadening when required by the method.
  • Use consistent fitting rules when comparing samples.

Limitations and interpretation

  • A mathematical fit can converge even when the selected peak model is physically inappropriate.
  • Strong asymmetry, unresolved overlap or insufficient points across a peak can make FWHM unreliable.
  • Fitted FWHM is not itself a crystallite size; further assumptions and corrections are required.

Continue your work

Start this workflow

This opens NotyPlot: Scientific Plotting & Peak Analysis in Workflow mode. The Tool / Workflow toggle remains available in the toolbar.

Start this workflow