XPS Peak 41 was a pioneering freeware tool that democratized XPS peak fitting for a generation of surface scientists. Its intuitive workflow—background subtraction, peak addition, non-linear least-squares fitting—captures the essential logic of spectral deconvolution. However, the software is now technically obsolete, crippled by OS incompatibility, primitive statistics, and the absence of modern quantification tools. While it serves as an excellent educational platform for understanding the principles of XPS fitting, researchers performing rigorous quantitative surface analysis must transition to contemporary software (commercial or open-source) that offers robust error analysis, standardized RSF databases, and support for modern spectrometer outputs. The legacy of XPS Peak 41 lies not in continued use, but in the foundational principles it taught a generation of users—principles that remain at the heart of XPS data analysis today.
Introduction
Despite obsolescence, XPS Peak 41 retains pedagogical value. Its minimalistic, manual approach forces users to understand the underlying physics: choosing a background, selecting peak shapes, and applying constraints. Students who learn on XPS Peak 41 often appreciate why modern software automates certain steps—and also learn to recognize when automation fails. Many research groups still use it for quick checks or when commercial licenses are unavailable, but this practice is discouraged for peer-reviewed publications due to the lack of traceable, reproducible fitting protocols. xps peak 41 software