Positive ionization and electron attachment of hexafluoropropylene oxide in different cluster environments

Abstract The hexafluoropropylene oxide, C 3 F 6 O (HFPO), is commonly used in technological processes involving low-temperature plasmas. In relevance to such processes, we investigate the electron ionization and attachment to HFPO molecules in various cluster environments. Either pure (HFPO) N clusters or the clusters deposited on larger argon nanoparticles (HFPO) N · Ar M are generated in molecular beams in vacuum. The cluster beam is intercepted with a beam of either slow (0–15 eV) or faster (70 eV) electrons, yielding negative or positive ions, respectively, and their mass spectra are recorded. Qualitatively, the spectra of free and Ar-deposited clusters are similar, exhibiting the same ion fragments. The cluster environment suppresses the fragmentation after ionization for both positively and negatively charged clusters, namely, the parent ions (HFPO) n +/− are present in the spectra. The fragmentation is more suppressed in the Ar-deposited clusters. In both the positive ionization and attachment, new fragmentation channels or ion-molecule reactions in the clusters lead to production of new fragments not observed in the gas phase. Mechanisms of these reactions and ionization processes are discussed.