[en] Variation trends across the AnO₂ series of An5f-electron covalent bonding and An5f→O3s, O2p→An5f charge transfer energies, are studied using DV-Xα relativistic spin-polarised computation of electronic structures applied to 11 'AnO₈' clusters, from ThO₈ to FmO₈. It is found that the binding energies of 5f orbitals, therefore the An5f-O2p hybridisation, are increasing though the 5f orbitals are localising across the An series. In our calculations, the 3s and 3p ionic-like orbitals of O^2- ions are included for the first time as LCAO-MO bases. Then, the conduction band is a mixing of O3s and An6d and its lower edge corresponds to an O3s-dominated state. Moreover, the calculated charge transfer (CT) energies of An5f→O3s and O2p→An5f transitions show the so-called tetrad effect when CT energies, respectively increasing and decreasing across the AnO₂ series. It is pointed out that the tetrad effect here comes mainly from the special spin-polarised pattern of 5f levels and the increasing general trend of 5f binding energies. (orig.)

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[en] Applications of the methods of electron-, X-ray, electron-photoelectron and Auger-spectroscopy for investigations into the thin surface layers of amoAphous metallic alloys, metal coatings and transition layers between the coating and the base metal for determination of reasons for microelectronics failures are considered

[en] Interfacial segregation, often confined to within a few atomic distances of the interface, can strongly influence the processing and properties of metals and ceramics. The thinness of such solute-enriched regions can cause them to be particularly suitable for study using surface sensitive microanalytical techniques such as Auger electron spectroscopy (AES). The application of AES to studies of interfacial segregation in metals and ceramics is briefly reviewed, and several examples are presented. 43 references, 14 figures

[en] Al(111) has been studied with angle-resolved photoelectron spectroscopy. A previously not observed surface state band located around the K point in the surface Brillouin zone is reported. The measured dispersion of the surface state band falls in an absolute electron energy band gap when the three-dimensional band structure from a new LAPW (Linearized-Augmented-Plane-Wave) calculation is projected onto the surface Brillouin zone of the (111) crystal face. The existence of this surface state has been theoretically predicted by several authors. Direct transitions between bulk bands are found to give significant contributions to the photocurrent. Experimentally deduced initial-state energy dispersion of the bulk transitions are compared to the corresponding dispersion obtained from the LAPW band structure calculation. (orig.)

[en] The electronic properties of the Ge(113):As adsorption system and their characteristic surface structure 1x1 and 2x1 were investigated using electron spectroscopy methods. The preliminary model which explain the electronic properties of the Ge(113):As system is proposed

[en] Electron irradiation induced phase separation in a sodium borosilicate glass was studied in situ by analytical electron microscopy. Distinctly separate phases that are rich in boron and silicon formed at electron doses higher than 4.0 x 10¹¹ Gy during irradiation. The separated phases are still in amorphous states even at a much high dose (2.1 x 10¹² Gy). It indicates that most silicon atoms remain tetrahedrally coordinated in the glass during the entire irradiation period, except some possible reduction to amorphous silicon. The particulate B-rich phase that formed at high dose was identified as amorphous boron that may contain some oxygen. Both ballistic and ionization processes may contribute to the phase separation

[en] Photoelectron holography requires a large data set covering a wide energy range. Changes in experimental conditions and sample surface regeneration during the course of measurement are often unavoidable or necessary, which can result in variations in measured intensity that must be normalized out before data processing. This normalization procedure can introduce a significant error, resulting in image degradation. To eliminate this problem, two methods of intensity self-normalization are introduced, one based on branching ratio measurements and the other based on logarithmic derivative measurements. The As-on-Si(111) system is chosen as a test case for these methods. Both the As and Si core levels are used to reconstruct the three-dimensional atomic structure for the top three atomic layers. The results from these two methods are mutually consistent and in good agreement with other available experimental and theoretical results. This paper also contains an analysis in regard to the use of an inner potential to account for surface refraction. Images are generated without refraction for an estimate of its effect on image quality. Similar analyses are carried out for the proper use of energy and angular window functions in the holographic transform, and for the effect of scattering phase shift that has been a major problem for direct data inversion. (c) 1999 The American Physical Society