Unraveling the radiative de-excitation of metal clusters by direct and indirect characterization of recurrent fluorescence

Even though small clusters have been investigated for decades, properties that directly depend on their excited states are poorly understood, with many cases in that experiment and theory fail to agree. One such property is the emission of photons as a deexcitation mechanism of hot clusters, a fundamental process with severe consequences on the production of mass-selected nanoparticles and even astrophysics. While such photons have been directly detected in small carbon molecules, this is not yet accomplished for small metal clusters, where indirect experiments suggest a very strong influence of radiation as a cooling channel. Established theoretical approaches, however, fail to predict the necessary electronic excited states that would explain the experimental observations, emphasizing our current lack of understanding on the phenomenon. This proposal aims to use ion trap experiments to directly detect and characterize such emitted photons, which will allow the collection of unique information on the photon emission process of metal clusters. The successful development of this proposal will close important gaps in our understanding on the excited state dynamics of these particles