Electron-cluster interactions: Excitation of neutral fragments in rare gases and simple molecules

The presented work on electron-cluster interactions utilizes mass and translational spectroscopic techniques that have traditionally been applied to atomic and molecular targets.{09}An investigation of the fluorescence and neutral metastable fragmentation of neutral clusters of various average sizes for different target compositions has been undertaken. Time-of-flight (TOF) mass spectroscopy of the ionized clusters has demonstrated an effective production source of clustered molecular (N₂O, H₂O, etc.) and rare gas (Ar, Kr, Xe, etc.) targets. The clustered targets were then studied, following electron impact, by observing the photon decay and metastable yield as a function of time (i.e., fluorescence and TOF methods). Excitation function techniques were used for specific time windows, corresponding to interesting photon and TOF features, by ramping the incident electron energy and observing the change in overall signal and appearance of energy thresholds. Furthermore, lifetime and kinetic energy analysis was utilized in order to elucidate the energy and dissociation pathways undertaken. Where available, this was compared to appropriate existing atomic, molecular, clustered, and solid results. However, it should be emphasized that, to our knowledge, these metastable yield results from clustered targets via electron impact are unique to this group.