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G. Hanel, T. Fiegele, A. Stamatovic, T.D. Märk
High Resolution Electron Ionization of N2O Clusters: Appearance Energies
Electron ionization cross sections for (N2O)n clusters have been investigated near the threshold with a newly constructed crossed beams apparatus using a hemispherical electron monochromator (HEM) to monochromatize the primary electron beam. Exploratory test measurements including electron attachment studies to CCl4 and CO and appearance energy (AE) determinations for some rare gases (Ar, Kr, Xe) and molecules (N2, O2, N2O, O2) measured for calibration purposes showed that the accuracy of the energy scale is better than 10 meV exhibiting a good linearity and that AE´s derived for these compounds agree within 20 meV with known photoionization data when using a novel data handling procedure (involving a simultaneous non-linear weighted least-squares fit of two functions).
Comparison of the presently derived appearance energies with earlier photoionization data shows a distinct difference in corresponding values attributed to different ionization mechanisms. Both data sets can be fitted successfully by a n-1/3 dependence yielding by extrapolation a value for the bulk photoelectric threshold (11.25 eV in the case of the photoionization data).
Zeitschrift für Physikalische Chemie, Oldenbourg Wissenschaftsverlag
Print ISSN: 0942-9352
Volume: 214, 08/2000
Pages: 1137