FRAGMENTATION OF DICATIONS STUDIED BY AUGER ELECTRON-ION COINCIDENCE EXPERIMENTS E. Fainelli, F. Maracci, M. Mastropietro, R. Platania and L. Avaldi IMAI del CNR , Area della Ricerca di Roma, CP10 00016 Monterotondo Scalo, ITALY An Auger electron-ion coincidence apparatus has been built at IMAI-CNR-Rome, to study the fragmentation of dications by electron impact. By tuning the energy of the dtected Auger electrons a state-to-state study of the fragmentation pattern in N2, NO and CH4 and a site dependent investigation in SF6 and Ccl4 have been performed.