Experimental Observation of Non-Exponential Auger-Meitner Decay of Inner-Shell-Excited CO

TL;DR

This study experimentally demonstrates that Auger-Meitner decay in inner-shell-excited CO molecules does not follow the typical exponential decay pattern, revealing complex lifetime behaviors influenced by molecular dynamics.

Contribution

It provides the first experimental evidence of non-exponential Auger-Meitner decay in a diatomic molecule and explains the underlying causes of lifetime variations.

Findings

Non-exponential decay observed in inner-shell-excited CO

Molecular lifetimes depend on ionic fragment kinetic energy

Decay dynamics differ from atomic cases

Abstract

Electronically excited atoms or molecules may deexcite by emission of a secondary electron through an Auger-Meitner decay. This deexcitation process is typically considered to be exponential in time. This is strictly speaking, however, only true for the case of an atom. Here, we present a study experimentally demonstrating the non-exponential time dependence of the decay of an inner-shell hole in a diatomic molecule. In addition, we provide an intuitive explanation for the origin of the observed variation of the molecular lifetimes and their dependence on the kinetic energy of the ionic fragments measured in coincidence with the photoelectrons.