Run the fitting engine. The software utilizes a non-linear least-squares minimization algorithm to adjust the unconstrained variables until the Chi-squared ( χ2chi squared ) error value is minimized.
Define the boundaries of the peak region. Apply a Shirley or Tougaard background and ensure the baseline aligns perfectly with the flat noise regions outside the peak.
XPS instruments often export data in proprietary formats. XPS Peak Fit requires data in a simple text format (ASCII).
What (like Origin or Excel) do you plan to use for your final figures?
XPSPEAK 4.1 is a lightweight Windows application. Because it is legacy freeware, it is often hosted on university or software repository sites.
Until then, mastering means staying ahead in surface analysis. Remember: garbage in, garbage out. No algorithm can fix poor data collection. Ensure your XPS instrument is properly calibrated and your samples are charge-compensated before even opening the software.
: While originally built for Windows 95/98, it is generally compatible with Windows XP, 7, 8, and 10. University of Warwick Standard Peak Fitting Workflow
A highly recommended free and open-source alternative that handles data directly from modern instruments.
While newer tools like KherveFitting have entered the scene, XPSPEAK 4.1's simplicity makes it ideal for teaching and routine lab workflows. Key features include:
Visually inspect the difference between your experimental data and the total fitting curve. A good fit will show purely random noise in the residual trace, without systematic waves or deviations.
XPS spectra consist of core-level peaks superimposed on a background caused by inelastic electron scattering. Accurate peak fitting requires modeling both this background and the specific peak shapes representing different chemical environments.