Inversion model for extracting chemically resolved depth profiles across liquid interfaces of various configurations from XPS data: PROPHESY

J Synchrotron Radiat. 2023 Sep 1;30(Pt 5):941-961. doi: 10.1107/S1600577523006124. Epub 2023 Aug 23.

Abstract

PROPHESY, a technique for the reconstruction of surface-depth profiles from X-ray photoelectron spectroscopy data, is introduced. The inversion methodology is based on a Bayesian framework and primal-dual convex optimization. The acquisition model is developed for several geometries representing different sample types: plane (bulk sample), cylinder (liquid microjet) and sphere (droplet). The methodology is tested and characterized with respect to simulated data as a proof of concept. Possible limitations of the method due to uncertainty in the attenuation length of the photo-emitted electron are illustrated.

Keywords: X-ray photoelectron spectroscopy; acquisition model; atmospheric surfaces; depth profile; inversion algorithm.