Threshold Electronhyphen;Impact Excitation and Negativehyphen;Ion Formation in XeF6and XeF4

摘要

Electronic excitation and dissociative electron attachment in XeF6and XeF4were investigated by studying the products of lowhyphen;energy electronndash;molecule collisions in the gas phase. The relative abundances of the major negative ions produced were recorded as a function of the electronhyphen;beam energy. Both molecules attached electrons at sim;0 and sim;5 eV and dissociated into a number of negativehyphen;ion products. The similar energy dependence of the various ion currents suggested that the fragment ions were competing for the electron attached to XeF6or XeF4. The threshold electronhyphen;impact excitation spectra were determined by means of the ldquo;SF6hyphen;electronhyphen;scavengerrdquo; technique. No evidence for lowhyphen;lying electronic states was found.