Hybridization of Al and O states in alpha- and gamma-alumina

Abstract

AhsbacL The p d a l A I and 0 valence spectral densities of a-and y-alumina in bulk and in the superficial zone of the samples are investigated using x-ray emission spectroscopy induced by electrons. These valence states are mixed over the whole width of the band. We show that changes in the atomic environment affect the hybndizalion of states io a narrow energy range. For the y-phase and superficial zones of the two phases. increased hybridization is'abserved. This is correhted with an increase in the covalent character of A I 4 bonds at the surface and the y-phase. Defect states are observed both in the gap between 0 2s and 0 2p stat= and in the optical gap; for the a-phase, a structure is seen at about 1 eV above fhe top of the valence band which we interpret as due to an oxygen-vacancy state.

MONOX: a characterization tool for the X-UV range

“…Such devices would improve the luminosity of the spectrometer and after a modification of the mechanism of the goniometer, we hope to get a rather bright Rowland X-UV spectrometer for the detection of light chemical elements (boron, carbon, nitrogen, oxygen). We note that the full width at half maximum of the O Kα emission is 12 eV, whereas it is determined to be 3 eV with a high-resolution bent crystal spectrometer [5].…”

Spectroscopic study of interfaces in Al/Ni periodic multilayers

“…An emission band is observed when a valence electron takes part in the electronic transition. Since valence electrons have low binding energies, the energy distribution of their emission band is very sensitive to the physicochemical environment of the emitting atom [1][2][3]. Thus, the shape and width of the emission band directly reflect the chemical bonding around the emitting atom.…”

Physico-chemical environment of Al impurity atoms in amorphous silica

“…Two oxides have been studied: the α-alumina where all the aluminum atoms are in octahedral environment (surrounded by an octahedron of oxygen atoms) and a poorly crystallized γ-alumina where the aluminum atoms are both in octahedral and in tetrahedral environment (surrounded by a tetrahedron of oxygen atoms) [9]. The width and maximum energy for the α-alumina sample are respectively 0.92 ± 0.04 eV and 1487.15 ± 0.03 eV.…”