Bayesian probability theory to identify false coincidences in coincidence experiments

Pascal Heim,Wolfgang Von Der Linden,Michael Rumetshofer,Markus Koch,Bernhard Thaler,Wolfgang E Ernst,G Cerullo,R Li,M Khalil,F Kärtner,J Ogilvie

doi:10.1051/epjconf/201920509025

Abstract

We describe a Bayesian formalism to analyse femtosecond pump-probe photoionization experiments with photoelectron-photoion coincidence (PEPICO) detection. This approach overcomes the drawback of extraordinary long data acquisition times of PEPICO detection. In extension to simply excluding false coincidences as previously [1], we here present an investigation of their influence on the underlying spectrum. The software is provided at https://github.com/fslab-tugraz/PEPICOBayes/.

Highlights

Coincidence experiments are widely spread and powerful spectroscopic techniques
At higher ionization rates the measured photoelectron-photoion coincidence (PEPICO) spectrum is obscured by false coincidences, so that the true spectrum cannot be obtained by the conventional PEPICO method [5]
While the Bayesian formalism was presented recently in detail [1], we here focus on the role of false coincidences by distinguishing between homo- and heteromolecular false coincidences and analyse their spectral distribution and how they distort the PEPICO spectrum

Summary

Introduction

Coincidence experiments are widely spread and powerful spectroscopic techniques. Recently we applied photoelectron-photoion coincidence (PEPICO) detection to femtosecond photoionization experiments [2]. We applied photoelectron-photoion coincidence (PEPICO) detection to femtosecond photoionization experiments [2].

Results

Conclusion