Measured and calculated absolute total cross-sections for the single ionization of CF x and NF x by electron impact

Abstract

Various additivity rules and the Deutsch—Märk (DM) formalism have been used to calculate total absolute electron-impact cross-sections for single ionization of the CF x ( x = 1–3) free radicals, the NF x ( x = 1,2) free radicals and the NF 3 molecule. A comparison is made with experimentally determined total single ionization cross-sections which have been obtained from recently measured absolute partial ionization cross-sections for the parent and dissociative ionization of these species. The overall best agreement between the measured and the calculated cross-sections in terms of the absolute values, the shapes and the cross-section ordering was obtained using a recently proposed “new” additivity rule. Common trends and tendencies in the ionization cross-sections within each class of targets, CF x and NF x , and between the two target families CF x and NF x are highlighted and a comparison will be made with the previously measured and calculated ionization cross-sections for the SiF x ( x = 1–3) free radicals.