Negative Chemical Ionization Mass Spectrometric Study on the Dissociative Electron Attachment Process of Chlorofluorocarbons and Bromofluorocarbons

The formation of a negative ion from chlorofluorocarbons(CCl4, Cl2FC–CClF2, Cl3C–CF3, Cl2FC–CCl2F, Cl3C–CClF2, C2Cl5F, C2Cl6, C2HCl3, C2Cl4) or bromofluorocarbons(Br2FC–CF3, BrF2C–CBrF2, Br2FC–CBrF2, CBr3F) was studied using negative chemical ionization mass spectrometry. The halide ion was mainly observed for all molecules. Among cholorofluoroethanes or bromofluoroethanes, a molecule with more chlorine or bromine atoms shows a higher intensity of Cl− or Br−. For C2Cl5F, C2Cl6, BrF2C–CBrF2, Br2FC–CBrF2, and CBr3F, the negative ions of the halogen molecule were also observed. Except for CBr3F, the ion would be produced by dissociative electron attachment.