AUGER AND RADIATIVE DECAY OF TRIPLY EXCITED STATES OF He-, Li, Be+, B2+ AND C3+PROJECTILES FOLLOWING ION-ATOM AND ION-MOLECULE INTERACTIONS A. Siems*, R. Bruch*, H. Merabet*, S. Bliman&, U. I. Safronova# *Department of Physics, University of Nevada Reno, Reno NV 89557 USA & Department de Physique, Universiti de Marne la Vallie, 93l66 Noisy LeGrand, France # Department of Physics, University of Notre Dame, Notre Dame, IN 46556 USA We present a comprehensive study of triply excited states of three electron systems. Experimentally we have demonstrated that these states are abundantly populated in ion-atom and ion-molecule collisions under single and multiple collision conditions. Using high resolution electron and EUV spectroscopy individual lines arising from He-, Li, Be+, B2+ and C3+so called "hollow atoms" with two K-shell vacancies have been resolved and identified. Theoretically, the excitation energies, probabilities for Auger and radiative decays and branching ratios of such hollow atom states have been calculated and the collisional excitation mechanism are discussed.