XPS, UPS AND XAES STUDIES OF THE ADSORPTION OF NITROGEN, OXYGEN, AND NITROGEN-OXIDES ON W(110) AT 300 AND 100 K .1. ADSORPTION OF N2, N2O AND NO2-N2O4

The adsorption of N2, N2O, and NO2 on W(110) at 300 and 100 K and the behaviour of the resulting adlayers upon heating have been investigated using XPS, UPS, and XAES. For O2 adsorption, some results of importance to the present investigation (sticking coefficients, XPS peaks and satellites, UPS, and XAES spectra) are also reported. The determinations of absolute coverages of O and N are based on these data. All nitrogen oxide layers are found to be deficient in N, as compared to the gaseous species. The occurrence of dissociative or molecular adsorption under the various conditions is determined. It is found that at 300 K, N2O and NO2 adsorption are completely dissociative, while at 100 K initial dissociation is followed by the formation of condensed layers of N2O and N2O4, respectively, with different growth characteristics. Adsorbate line widths in UPS and line shapes in XPS are discussed. The usefulness of the various methods for fingerprinting is compared. © 1979.