KherveFitting: An Open Source Software for Fitting X‐Ray Photoelectron Spectroscopy Data

ABSTRACT KherveFitting is a software written in Python and designed for fitting X‐ray photoelectron spectroscopy (XPS) data. It provides a user‐friendly graphical interface for researchers in materials science and surface analysis, offering features that include multiple background subtraction methods, various peak fitting models, and automated multipeak fitting with customisable constraints. This software aims to fill a gap in the market for XPS analysis tools, providing a freely available solution for users. This paper describes the software architecture and its theoretical background, including fitting algorithms and peak models. Its performance is validated by directly comparing quantification accuracy and peak fitting capabilities against established commercial software packages, demonstrating robust and reliable results across diverse test cases including ionic liquids, conducting oxides, and rare earth materials.