Fluorescence decay of naphthalene studied in an electrostatic storage ring, the Mini-Ring

Abstract

The cooling of naphthalene cations (C10H8)+ has been studied in a compact electrostatic ion storage ring, the Mini-Ring. A nano second laser pulse of 532nm (2.33eV) was used to probe the internal energy distribution every millisecond during the storage time up to 5ms. The evolution of the internal energy distribution of the stored ions was simulated with a model taking into account the dissociation and the radiative decay processes. Calculated decay curves were fitted to the corresponding laser induced neutral decays. For a laser power of 200μJ/pulse, a good agreement between experiment and modeling was found using an initial Gaussian energy distribution centered to 5.9eV and a fluorescence decay rate varying from 200 to 300s−1 in the energy range from 6 to 7eV. This fast decay was attributed to the delayed Poincaré fluorescence process.