ESCA , and

X-ray scattering studies at a renewed pc-Ag/electrolyte interface366,823 provide evidence for assuming that fast relaxation and diffu-sional processes are probable at a renewed Sn + Pb alloy surface. Investigations by secondary-ion mass spectroscopy (SIMS) of the Pb concentration profile in a thin Sn + Pb alloy surface layer show that the concentration penetration depth in the solid phase is on the order of 0.2 pm, which leads to an estimate of a surface diffusion coefficient for Pb atoms in the Sn + Pb alloy surface layer on the order of 10"13 to lCT12 cm2 s i 820 ( p,emicai analysis by electron spectroscopy for chemical analysis (ESCA) and Auger ofjust-renewed Sn + Pb alloy surfaces in a vacuum confirms that enrichment with Pb of the surface layer is probable.810... 

We thank the European Commission (Contract No. C11-CT93-0361) for financial support. The experimental help of S. Badrinarayanan and R.F. Shinde in collecting the ESCA and ESR spectra, respectively, is gratefully acknowledged. 

We report the discovery of a new Pd-Sn catalyzed hydrogenolysis reaction to produce thiol product in high yields. The relationship between catalyst activity and surface characterization (chemisorption, ESCA, and in situ temperature-dependent XRD,) has aided om understanding of the reasons why these catalysts are sulfur resistant, extremely active, and activated at certain temperatures and pressures. The predominant mode of deactivation appears to be the formation of Pd-CN species rather than the formation of Pd-S species on the surface of the catalyst. 

All HEC catalysts have low Pt dispersion and high Pt to C ratios (ESCA) and there is more Pt on the edges of the support. These catalysts are more selective towards the hydrogenation of the C=0 bond, as compared with the corresponding HDC catalysts. 

Thanks are due to Nancy Brungard, and George Munzing of Engelhard for the ESCA and TEM works. 

Whereas ESCA and other surface specific techniques are often the obvious method of choice, IR-ATR may be a suitable technique when the composite material is heavily filled, and the IR radiation does not penetrate to far into the sample material. An advantage of, e.g., IR is that the sample can be investigated under ambient conditions rather than under a high vacuum, as required with techniques such as ESCA. 

ESCA and AUGER have been carried out on several metals and in all cases the metal has been shown to be in the zerovalent state. Bulk analysis also clearly shows that the metal powders are complex materials containing in many cases significant quantities of carbon, hydrogen, oxygen, halogens, and alkali metal. 

This indicates that a new characterization which could not be achieved by ESCA and FTIR is expected. 

There is no such thing as a completely non-destructive analysis. Upon interaction of the beam with the sample, a series of surface-disruption phenomena can occur. This fact is illustrated in Table 14.10 for the four major surface analysis techniques mentioned above. The least surface disruption occurs in ESCA and the measurements are characteristic of the surface. However, when charged particles such as electrons and ions are... 

Proton and C-nmr, ESCA, and Raman studies provide a wealth of information which unfortunately is not subject to a unique interpretation. The main conclusion to be drawn therefore is that the structure of the solvent stabilized cation is still unproven. Gas phase estimates of the heat of formation of the norbomyl cation imply a rather marked stability of the stmcture relative to other secondary ions (Kaplan et al., 1970). When combined with other estimates of the heat of formation of the t-butyl cation, however, these data suggest that hydride transfer from isobutane to the norbomyl ion will be endothermic by 6 to 15 kcal mole . This is contrary to experience in the liquid phase behaviour of the ion, and the author s conclusion that their observation of enhanced stability is evidence of stabilization by bridging deserves further scmtiny. 

KCl solution for 24 hours. After being removed from the salt solutions, the membranes were rinsed thoroughly with distilled, deionized water. The salt solutions were analyzed with a Varlan 175 series atomic absorption spectrometer (AAS). Na and K concentrations were determined using the 590.8 nm and 768.5 nm absorption bands, respectively. Before and after the ion-exchange studies, the membranes were dried and analyzed with ESCA and NAA. 

As representative techniques of the second group, we discuss two methods x-ray photoelectron spectroscopy (XPS), sometimes referred to as electron spectroscopy for chemical analysis (ESCA) and Auger electron spectroscopy (AES). The main principle of the first method (XPS) is the excitation of electrons in an atom or molecule by x-rays. The resulting electrons carry energy away according to the formula... 

Hopfgarten, F. (1978). Surface study of carbon fibers with ESCA and Auger electron spectroscopy. Fibre Sci. Technol. II, 61-19. 

Soroczak, M. M., Eaton, H. C. Tittleb aum, M. E. 1987. An ESCA and SEM study of changes in the surface composition and morphology of low-calcium coal fly ash as a function of aqueous leaching. Materials Research Society Symposium Proceedings, 86, 37-47. 

The ten chapters are organized into three main sections. The first four chapters (Jansson) introduce the reader to basic concepts and progress through a survey of both traditional linear and modern nonlinear methods. Chapters 5 (Jansson), 6 (Blass and Halsey), and 7 (Halsey and Blass) detail specific applications of a proven method to the fields of electron spectroscopy for chemical analysis (ESCA) and high-resolution infrared spectroscopy via three different instrumental techniques. Also included are brief examples of applications to nuclear and Raman spectroscopy. The final section, Chapters 8 (Frieden), 9 (Howard), and 10 (Howard), illustrates recent work and reveals some directions for potential future research. 

Although as will become apparent if we consider any one level of information available from ESCA and compare this with that available from the most competitive of the other available spectroscopic technique for the particular case in question, it is invariably the case that ESCA compares relatively unfavourably. The most distinctive feature of ESCA as a spectroscopic tool however which sets it apart from any other is the large range of available information levels and these are shown in Table 2. For a fuller description see Ref.2. ... 

X-Ray Photoelectron Spectroscopy (XPS). This technique is also known as electron spectroscopy for chemical analysis (ESCA), and as this name implies, it is a surface analytical technique. At present it is probably the most versatile and generally applicable surface spectroscopic technique. It is called XPS because of the type of beam used to study the interfacial region, that is, X-rays. These X-rays consist of monochromatic radiation—radiation of a given energy—emitted by a metal target bombarded by an electron beam of several kiloelectron volts of kinetic energy... 

In Section II, we survey the structural analyses of ylides, summarizing the reported X-ray crystal structures, electron diffraction studies and calculational determinations. In Section III, we present spectroscopic data (primarily UV, NMR, ESCA and EPR) that pertain to characterizing the bonding in the ylides. Finally, we attempt in Section IV to bring together all the summarized evidence to present a cogent and coherent picture of the bonding in the ylides. 

X-Ray Photoelectron Spectroscopy. During the 1960s, Kai Sieg-bahn and co-workers (12) developed a surface-sensitive, high-resolution photoelectron spectroscopy that used x-rays as the irradiation source. He designated it as Electron Spectroscopy for Chemical Analysis or ESCA. The generic denotation for x-ray photoelectron spectroscopy of XPS is more accurate than ESCA and is preferred for clarity and for indicating the relationship of UPS. 

Techniques that enable the observation of specific valencies of cations include E.S.R., 7-resonance spectroscopy and ESCA, and have been considerably improved in the recent years. 

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