XPS peak fitting, online.
XPSLab lets you import raw XPS spectra, subtract a background, fit peaks, and export publication-ready results, all in your browser. No desktop software to install and no spreadsheets to maintain.
Free during beta — no credit card required.
The basics
What is XPS peak fitting?
In X-ray photoelectron spectroscopy, a single measured region (for example C 1s or O 1s) is usually a sum of several overlapping components, each corresponding to a different chemical state. Peak fitting separates those components so you can identify the chemical environments present and estimate how much of each there is.
Workflow
The typical workflow
- 1
Import and calibrate
Load the raw spectrum and correct for sample charging. A common approach is referencing adventitious carbon C 1s to 284.8 eV, though the right reference depends on your sample.
- 2
Subtract the background
Choose a background model suited to the region, such as linear, Shirley, or Tougaard.
- 3
Add peak components
Use Gaussian-Lorentzian line shapes (asymmetric where appropriate for metals) and set sensible constraints on position, width, and area.
- 4
Constrain doublets
For spin-orbit split core levels, fix the area ratio (p: 2:1, d: 3:2, f: 4:3) and the splitting between the pair.
- 5
Check and quantify
Inspect the residual, confirm the fit is chemically reasonable, then use the peak areas for quantification.
Why XPSLab
Fit XPS spectra in the browser
Interactive fitting
Adjust components and constraints with live previews as you change parameters.
Background subtraction and quantification
Remove the background, fit, and quantify in the same workspace.
Batch processing
Fit many spectra at once and keep a full run log.
Reproducible reports
Your fit parameters are stored alongside the data, so results can be traced and repeated.
FAQ
Frequently asked questions
- Is XPSLab free?
- XPSLab is free during the beta, and no credit card is required.
- Do I need to install anything?
- No. XPSLab runs in your web browser.
- Which instruments' files can I import?
- XPSLab is built to import raw spectra from major XPS instruments. Contact us if you need a specific format.
Start fitting spectra today
Free during beta — no credit card required.