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Periodically stepped NiO(100) surfaces were prepared and characterized with low-energy electron diffraction (LEED), Auger electron spectroscopy (AES), X-ray photoelectron spectroscopy (XPS), and temperature-programmed desorption (TPD). Two vicinal NiO(100) single-crystal samples were cut, oriented, and polished with regular, repeating monatomic steps in six-atom or seven-atom terrace widths. LEED diffraction patterns showed characteristic spot-splitting that corresponded to the appropriate terrace and step height. The nonstepped and stepped NiO(100) surfaces were exposed to bromobenzene at 130 K first to produce a molecularly adsorbed monolayer species and then, with increased exposure, a multilayer adsorbate. An additional adsorbate species, observed only on the stepped surfaces, was found to desorb at 145 K by two competing pathways. One pathway, which saturates at low coverages, leaves bromine behind on the substrate and results in dehalogenation. The other pathway yields molecular desorption at 145 K, but is only observed in detectable amounts after the dehalogenation pathway is saturated. On both stepped and nonstepped NiO(100) substrates, adsorbed bromine resulting from dehalogenation processes appears as nickel bromide, determined by the Br 3p XPS data.

Surface composition and structure of Co 3 O 4 (110) and the effect of impurity segregationThe Fuchs-Kliewer phonon spectrum of single crystal Co 3 O 4 ͑110͒ has been treated with a Fourier transform log deconvolution method, which removes multiple scattering features from the single loss spectrum. Auger electron spectroscopy ͑AES͒, x-ray photoelectron spectroscopy ͑XPS͒ and low-energy electron diffraction ͑LEED͒ were first used to characterize the Co 3 O 4 crystal establishing the cleanliness, composition, and order of the ͑110͒ surface. High resolution electron energy loss spectroscopy ͑HREELS͒ was then used to obtain the phonon spectrum for an incident electron energy of 3.77 eV. Due to the strong dipole cross section for the Fuchs-Kliewer phonon modes, intense multiple electron scattering was detected, which provided a complicated and overlapping combination of all possible loss modes. Deconvolution removed the multiple loss modes to produce well-resolved Fuchs-Kliewer fundamental phonon losses at 218, 373, 598, and 682 cm −1 ͑27.0, 46.2, 74.1, and 84.6 meV͒. These values are compared to the fundamental loss energies obtained by resolving the overlapping peak structure with standard peak fitting procedures, which confirmed the single loss energies obtained with the deconvolution procedure. Deconvolution results from the four fundamental phonon spectrum of single crystal Co 3 O 4 ͑110͒ were also compared to those from the simpler spectra of CoO͑100͒ and thin-film CoO͑100͒-Co 3 O 4 epitaxy and some practical aspects of the deconvolution process discussed in this context.

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