LINE-SHAPES FOR ATTACHMENT OF THRESHOLD ELECTRONS TO SF6 AND CFCL3 - THRESHOLD PHOTOELECTRON (TPSA) STUDIES OF XE, CO, AND C2H2

Using the technique of threshold photoelectron spectroscopy by electron attachment (TPSA), the shapes of the threshold electron attachment cross sections for SF6 and CFCl3 are determined by direct photoionization measurements of the 2P1/2 level of Xe +. The observed TPSA line shape is deconvoluted using a Lorentizian attachment profile with full-width at half-maximum of 30 meV for SF6 and 25 meV for CFCl3. In addition, TPSA spectra of the ground electronic states of CO+ and C2H2+ are reported. In CO+ the intensity of the threshold spectral features are dominated by autoionization, while for the vibrational features of C 2H2+ direct photoionization is more important. The two processes (autoionization and direct ionization) are characterized by different TPSA spectral line profiles. © 1979 American Institute of Physics.