Dissociative electron attachment to c-C4F8 molecules and clusters.

The electron attachment and dissociative electron attachment to gas phase octafluorocyclobutane (c-C4F8) and to its clusters have been measured. The majority of the gas phase products were already reported earlier and have been successfully confirmed in this work. In addition, two new fragments c-C4F7− and C2F5− have been detected at electron energies ∼3.6 eV and 3.1 eV respectively. The parent molecular ion c-C4F8− has been detected not only at the expected ∼0 eV energy, but also with a weak resonance at ∼0.66 eV as well. Contrary to gas phase measurements, the electron attachment to c-C4F8 molecular clusters has been measured for the first time. The dominant ionic products at electron energies ∼0 eV are the monomer, dimer and trimer of ((c-C4F8)n=0,1,2·c-C4F8)−, ((c-C4F8)n=0,1,2·c-C4F7)− and ((c-C4F8)n=0,1,2·F)−. The higher energy resonances at ∼4 eV have been associated with the metastable c-C4F8− ion as well as with possible electron scavenging processes in clusters. Finally, above 8 eV the core-excited electron attachment has been observed. [ABSTRACT FROM AUTHOR]