X-ray photoelectron spectra and Auger studies of the surface oxidation of cobalt

Surface oxidation of Co has been investigated at different temperatures in the 300–600 K range at oxygen exposures upto 106 L by XPES and AES techniques. In the XPES, both the valence band and core level bands have been employed to monitor the oxidation while in the AES, metal Auger intensity ratios as well as O(KLL)/Co(L23M45M45) ratios have been examined. Only CoO is formed on the surface at high oxygen exposures at and above 500 K.

Structural characterization of γ-terpinene thin films using mass spectroscopy and X-Ray photoelectron spectroscopy

Understanding the polymerization mechanism of a precursor is indispensable to enhance the requisite material properties. In situ mass spectroscopy and X-ray photoelectron spectroscopy is used in this study to understand the RF plasma polymerization of γ-terpinene. High-resolution mass spectra positive ion mass spectrometry data of the plasma phase demonstrates the presence of oligomeric species of the type [M+H]+ and [2M+H]+, where M represents a unit of the starting material. In addition, there is abundant fragmented species, with most dominant being [M+] (136 m/z), C10H13+ (133 m/z), C9H11+ (119 m/z), and C7H9+ (93 m/z). The results reported in this manuscript enables to comprehend the relationship between the degree of incorporation of oxygen and the rate of deposition with the input RF power.

Valence fluctuation in some Yb intermetallics by X-ray photoemission and X-ray absorption

The valence state of Yb in some of its intermetallics, YbNi2Ge2, YbCu2Si2 and YbPd2Si2 has been investigated by LIII(Yb) absorption edges and X-ray pnotoelectron spectra in the 4f and 4d regions. These studies establish the presence of mixed valence in all three systems and illustrate the utility of 4f and 4d spectra in the study of mixed valence in Yb compounds.

Crystallization and preliminary X-ray studies of the anti-T lectin from peanut (Arachis hypogaea)

The anti-T lectin from peanut (Arachis hypogaea) crystallizes in the orthorhombic space group P21212 with one tetrameric molecule (Mr 110,000) in the asymmetric unit in a cell of dimensions a = 129.3 Å, B = 126.9 Å and C = 76.9 Å. The crystals are suitable for high resolution work.

Chlorination of silver dosed with potassium and barium in presence of oxygen: An X-ray photoelectron spectroscopy study

XPS studies show that the presence of chemisorbed chlorine stabilizes and also enhances molecular dioxygen species on Ag surfaces dosed with either K or Ba. The surface atomic oxygen is found to become depleted on chlorination. The variation in the nature of surface species with respect to temperature shows chlorine-induced diffusion of atomic oxygen into the subsurface region at 300 K. For coverages of potassium up to 8 × 1014 atoms/cm2, preferential chloridation of Ag occurs while at higher potassium coverages, KCl formation is distinctly observed on the surface. In the case of barium, two types of adsorbed chlorine species, Cl(α) and Cl(β), associated with Ag and Ba, respectively, are clearly seen even at low barium coverages. This is believed to be due to the higher valence occupation of barium compared to potassium. The Cl(α) species associated with Ag is found to occupy a preferred site on both K- and Ba-dosed surfaces, involving chemisorptive replacement of O(α) to the subsurface region.

Novel Oxidation of Pyridoxal in Ternary Metal Complexes. An X-Ray Study of the Products

Attempts to prepare ternary metal complexes of pyridoxylidene-amino acid Schiff bases culminated in the oxidation of pyridoxal to pyridoxic acid or to its lactone and their complex formation, as evidenced from an X-ray study.

X-Ray Spectroscopic Studies of the Surface Species in Co-Mo-Al2O3 Hydrodesulphurization Catalysts

Octahedrally coordinated CoII and MoIV species are present on the surfaces of sulfided Co-Mo-Al2O3 catalysts used for hydrodesulfurization. They were characterized by XPE, EXAFS and XANES data. An excess of sulfur in the surface species can be explained in terms of the presence of S[stack 22 ] ions. Disulfide bridges could play a role in the hydrodesulfurization.

Chemical ordering in As-Se glasses: X-ray absorption edge and XPES studies

X-ray absorption edge and X-ray photoelectron spectroscopic studies of As-Se glasses seem to support a chemical ordering model.

X-ray absorption spectroscopic study of the mixed valence system CePd3

Mixed valency in CePd3 has been examined by a study of the LIII (Ce) absorption edge in this compound as well as other model compounds. In CePd3, peaks characteristic of 3+ and 4+ states of Ce are found to be separated by 2 eV.

CO2-laser induced X-ray emission from high density gaseous targets

A theory for the emission of X-rays from a high density gaseous plasma interacting with CO2 laser is given. It predicts a sharp increase in the X-ray intensity for densities close to the critical.

Theory of CO2-laser induced x-ray emission from high density gaseous targets

Abstract is not available.