Chemical shifts in X-ray and photo-electron spectroscopy: a historical review

2004 ◽  
Vol 137-140 ◽  
pp. 59-71 ◽  
Author(s):  
Ingvar Lindgren
1972 ◽  
Vol 16 ◽  
pp. 90-101 ◽  
Author(s):  
R. D. Davies ◽  
H. K. Herglotz ◽  
J. D. Lee ◽  
H. L. Suchan

AbstractA new ESCA (electron spectroscopy for chemical analysis) instrument has been developed to provide high sensitivity and efficient operation for laboratory analysis of composition and chemical bonding in very thin surface layers of solid samples. High sensitivity is achieved by means of the high-intensity, efficient X-ray source described by Davies and Herglotz at the 1968 Denver X-Ray Conference, in combination with the new electron energy analyzer described by Lee at the 1972 Pittsburgh Conference on Analytical Chemistry and Applied Spectroscopy. A sample chamber designed to provide for rapid introduction and replacement of samples has adequate facilities for various sample treatments and conditioning followed immediafely by ESCA analysis of the sample.Examples of application are presented, demonstrating the sensitivity and resolution achievable with this instrument. Its usefulness in trace surface analysis is shown and some “chemical shifts” measured by the instrument are compared with those obtained by X-ray spectroscopy.


2002 ◽  
Vol 09 (05n06) ◽  
pp. 1661-1666 ◽  
Author(s):  
M. GARCIA-MENDEZ ◽  
N. ELIZONDO-VILLARREAL ◽  
M. H. FARIAS ◽  
G. A. HIRATA ◽  
G. BEAMSON

By means of pulsed laser deposition we prepared Co–Ni/p-Si thin films upon a Si(100) substrates. Samples were thermally treated in vacuum in order to promote silicide formation. From X-ray photo-electron spectroscopy (XPS) analysis, we detected chemical shifts of the Co2p and Ni2p transitions, characteristic of silicide binding energy, at the respective ranges of 778.3–778.6 and 853.2–853.6 eV. By means of high resolution transmission electron microscopy (HRTEM) we identified some nanocrystalline regions belonging to CoSi 2, Ni 2 Si and NiSi 2 structures. We also appreciate that the resulting films are of a polycrystalline nature.


The bombardment of (110) diamond surfaces by 600 eV rare gas and nitrogen ions, and the subsequent erosion of the partially disordered surfaces by microwave-excited nitric oxide at 380 °C, have been studied by means of X-ray induced electron spectroscopy. Both implant and substrate peaks were monitored as a function of erosion time to give semiquantitative depth profiles for both the ion-induced disorder in the substrate and the concentrations of the implanted species. Uptake of the rare gases at the surface amounted to 2-5 at. %, whereas that of nitrogen reached about 50 at. %. Great heteroatom penetration (200-1000 Å) occurred in all cases, especially during implantation at 380 °C, although the majority of the implanted species always lay within 25 Å of the surface. The surface concentration of neon (only), however, was greatly reduced by heating, so that its concentration profile peaked 10 Å below the surface. Nitrogen, xenon and neon penetrated to greater depths than did argon or krypton, and also induced greater disorder; but the most extensive disruption, near-total throughout ca . 50 Å, resulted from He + bombardment. Comparisons of Auger and photoelectron energies between gas and solid indicated the extra-atomic relaxation energy for inert monatomic implants to be ca . 3 eV. During erosion of Kr + and Xe + bombarded surfaces, however, the emergence of additional peaks with reduced relaxation energies showed that krypton and xenon (only) could aggregate in subsurface microcavities. Implanted nitrogen exhibited chemical shifts (after correction for relaxation) of up to 4.7 eV, comparable with those in nitriles, and <100> split interstitial sites are proposed as possible locations for these bonded heteroatoms. Some implications of these results are discussed.


1982 ◽  
Vol 79 ◽  
pp. 325-329 ◽  
Author(s):  
M. Y. Apte ◽  
C. Mandé ◽  
J. P. Suchet

2002 ◽  
Vol 713 ◽  
Author(s):  
Roman V. Bogdanov ◽  
Yuri F. Batrakov ◽  
Elena V. Puchkova ◽  
Andrey S. Sergeev ◽  
Boris E. Burakov

ABSTRACTAt present, crystalline ceramic based on titanate pyrochlore, (Ca,Gd,Hf,Pu,U)2Ti2O7, is considered as the US candidate waste form for the immobilization of weapons grade plutonium. Naturally occuring U-bearing minerals with pyrochlore-type structure: hatchettolite, betafite, and ellsworthite, were studied in orders to understand long-term radiation damage effects in Pu ceramic waste forms. Chemical shifts (δ) of U(Lδ1)– and U(Lβ1) – X-ray emission lines were measured by X-ray spectrometry. Calculations were performed on the basis of a two-dimensional δLá1- and δLδ1- correlation diagram. It was shown that 100% of uranium in hatchettolite and, probably, 95-100% of uranium in betafite are in the form of (UO2)2+. formal calculation shows that in ellsworthite only 20% of uranium is in the form of U4+ and 80% of the rest is in the forms of U5+ and U6+. The conversion of the initial U4+ ion originally occurring in the pyrochlore structure of natural minerals to (UO2)2+ due to metamict decay causes a significant increase in uranium mobility.


Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2058
Author(s):  
Jordi Fraxedas ◽  
Antje Vollmer ◽  
Norbert Koch ◽  
Dominique de Caro ◽  
Kane Jacob ◽  
...  

The metallic and semiconducting character of a large family of organic materials based on the electron donor molecule tetrathiafulvalene (TTF) is rooted in the partial oxidation (charge transfer or mixed valency) of TTF derivatives leading to partially filled molecular orbital-based electronic bands. The intrinsic structure of such complexes, with segregated donor and acceptor molecular chains or planes, leads to anisotropic electronic properties (quasi one-dimensional or two-dimensional) and morphology (needle-like or platelet-like crystals). Recently, such materials have been synthesized as nanoparticles by intentionally frustrating the intrinsic anisotropic growth. X-ray photoemission spectroscopy (XPS) has emerged as a valuable technique to characterize the transfer of charge due to its ability to discriminate the different chemical environments or electronic configurations manifested by chemical shifts of core level lines in high-resolution spectra. Since the photoemission process is inherently fast (well below the femtosecond time scale), dynamic processes can be efficiently explored. We determine here the fingerprint of partial oxidation on the photoemission lines of nanoparticles of selected TTF-based conductors.


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