X-ray photoelectron spectroscopy of alkali tellurite glasses

Local structure and redox state of copper in tellurite glasses

“…One further notes that the measured area ratio, [NBO/TO], increases roughly linearly with increasing CuO concentration. The ability to distinguish the BO and NBO peaks in the XPS spectra for this TeO 2 glass system is unlike the earlier XPS study carried out on alkali oxide-tellurite glasses where only a single symmetrical Gaussian-Lorentzian peak was observed from which BO and NBO could not be separated [26] and hence a change in the coordination structure of the tellurium atom was inferred from the Raman spectra. Assuming the copper atoms in the glass behave as network modifiers of the TeO 4 trigonal bipyramid structure (introducing NBO), then each copper oxide molecule will contribute two NBO atoms in the glass [27].…”

“…The smaller electronegativity of Cu (1.90) as compared to that of Te (2.1) should result in a small increase in the electron density at the Te atom with the addition of Cu and correspondingly a small decrease in the Te 3d binding energies, as observed. Moreover, the 0.3 eV shift in the Te 3d binding energies for the most concentrated CuO-containing tellurite glasses is much smaller than the shifts observed in the Te 3d spectra from an earlier XPS study on R 2 O-TeO 2 (R: Li, Na, K, Rb and Cs) glasses [26]. Thus it is reasonable to speculate that the local glass structure remains trigonal bipyramid (TeO 4 ) as the Te atoms are replaced by Cu atoms.…”

TeO2–WO3 Glasses: Infrared, XPS and XANES Structural Characterizations

“…For the crystallized references, the O1s peaks consist of only a single and symmetric Gaussian-Lorentzian peak with a small FWHM E1.2 eV. For (1Àx)TeO 2 -xWO 3 glasses with x ¼ 0:05 and 0.30, the registered FWHM of the only one component O1s peak is slightly larger, E1.5 eV, and is independent of glass compositions, Table 1 , 529.6 eV) is sufficiently large (0.9 eV) to be registered at least as an asymmetry of the O1s peak and an increase of the FWHM (37,38).…”

Classification of Light-Induced Desorption of Alkali Atoms in Glass Cells Used in Atomic Physics Experiments

“…The surface density of this kind of adsorbate depends on that of the defect sites, which is affected by the processing history of the glass surface as well as by the type of the glass. Although most defect sites would be occupied by various species such as carbonates and hydroxides [40] before cell preparation due to, for example, exposure to air, it is reasonable to assume that some of these defect sites would become unoccupied and reactive to alkali atoms during the evacuation and baking processes.…”