Formation of Gaseous Negative Ions of Fluoro and Trifluoromethyl Derivatives of C60 Fullerene Studied by Knudsen-Cell Mass Spectrometry

Experimental procedures are described for producing negative ions of fluoro and trifluoromethyl derivatives of C60 in the vapor phase and characterizing them by Knudsen-cell mass spectrometry. Some common aspects of the formation of such ions are established, and the associated ion-molecule equilibria are investigated. Electron affinity data are presented for C60(CF3)2n molecules. It is shown that, upon ionization, the fluorofullerenes tend to loose one or several fluorine atoms.