Electron attachment by haloalkenes and halobenzenes

Electron transmission spectra and mass spectra of negative ions from dissociative electron attachment have been obtained for four series of halogenated alkenes: vinyl halides, chloroethylenes, halobenzenes, para-dihalobenzenes. The stabilizing effect of halogen substituents upon anion state energies is obvious. Systematic observations permit assignment of summation and product anion states. Dissociative attachment usually proceeds through the product anion state. An enormous enhancement of the cross section for dissociative attachment of threshold electrons is observed in some cases