Dissociative electron attachment in chlorofluoromethanes and the correlation with vertical attachment energies

The total dissociative electron attachment (DEA) cross sections of the chlorofluoromethanes are determined in an electron beam experiment and correlated with the vertical attachment energies (VAEs) for formation of the lowest temporary anion states of these compounds. The latter are determined independently by electron transmission spectroscopy and correspond to the energies of the anions at the equilibrium geometries of the neutral molecules. As we observed previously in the chloroalkanes, the peak DEA cross sections are well correlated with VAEs. For values of VAEs between 0.9 to 3.0 eV, the peak DEA cross sections vary by more than four orders of magnitude. This is attributable in part to the remarkably monotonic variation of the temporary anion widths, arising from their finite lifetimes, over this range of VAE. (C) 2001 Elsevier Science B.V.