INTRACLUSTER ION-MOLECULE REACTIONS WITHIN CF3H CLUSTER SYSTEM

Abstract

Ion/molecule reactions occurring within CF3H cluster ions are investigated mass spectrometrically utilizing electron impact ionization. The study of fragmentation patterns indicates that the major reactive process is the formation of protonated cluster ions via the ejection of CF3 from the energized cluster ion. The parentages of major fragment ions, e.g., (CF3H)nX+(X = CF2H and CF3, n greater-than-or-equal-to 1), are assigned from both pressure and electron energy dependence of these ions. The studies suggest that the precursors of (CF3H)nCF2H+ ions are the protonated CF3H clusters whereas the (CF3H)nCF3+ cluster ions are formed by a direct dissociative ionization of neutral (CF3H)q (q > n) clusters. The other fragment ions are produced by the consecutive ejection reactions of neutral molecules (HF, H-2, and F2). Studies of the reactions within mixed CF3H/CH4 clusters also support the possible reactive pathways for the formation of fragment ions.