High-resolution energy-loss

Papagno, L., Shen, X. Y., Anderson, J., Spagnolo, G. S. and Lapeyre, G. J. Hydrogen adsorption on Ge(100) studied by high-resolution energy-loss spectroscopy. Physical Review 34, 7188-91 (1986). 

High-resolution energy-loss spectroscopy (HREELS) spectra of the oli-gothiophenes 4T through 8T have been reported (94JCP(101)6344 95JST (348)405). 

The example above shows that heterogeneous catalysts are multifunctional materials not at the nanometer but even at the atomic scale. A detailed structural understanding is a prerequisite for a targeted development of these eatalysts. This would be impossible without the help of modem TEM techniques. It can be expeeted, that the next generation of TEM instmments with Cs-corrected eondensor- and objective lenses in combination with high resolution energy electron loss spectrometers ean reveal stmetural and chemical details of eatalysts even at the atomie seale [10,11]. 

Several techniques that provide information about composition and structure on the molecular level were discussed. For instance, secondary ion mass spectroscopy (SIMS), XPS which provide information about surface composition and the chemical environment and bonding of surface species, and ultraviolet photoelectron spectroscopy (UPS), which probes the density of electronic states in the valence band of materials. Also, the low energy electron diffraction (LEED) and high resolution energy electron loss spectroscopy (HREELS) are electronscattering techniques that are uniquely suited to yield the structure of the surface... 

HREELS high resolution energy electron loss spectroscopy... 

Fig. VIII-10. (a) Intensity versus energy of scattered electron (inset shows LEED pattern) for a Rh(lll) surface covered with a monolayer of ethylidyne (CCH3), the structure of chemisorbed ethylene, (b) Auger electron spectrum, (c) High-resolution electron energy loss spectrum. [Reprinted with permission from G. A. Somoijai and B. E. Bent, Prog. Colloid Polym. ScL, 70, 38 (1985) (Ref. 6). Copyright 1985, Pergamon Press.]...

HREELS High-resolution electron energy-loss spectroscopy [129, 130] Same as EELS Identification of adsorbed species through their vibrational energy spectrum... 

In eollisional exeitation, translational energy of the projeetile ion is eonverted into mtemal energy. Sinee the exeited states of the ions are quantized, so will the translational energy loss be. Under eonditions of high energy resolution, it is... 

As the table shows, a host of other teclmiques have contributed a dozen or fewer results each. It is seen that diffraction teclmiques have been very prominent in the field the major diffraction methods have been LEED, PD, SEXAFS, XSW, XRD, while others have contributed less, such as NEXAFS, RHEED, low-energy position diffraction (LEPD), high-resolution electron energy loss spectroscopy (HREELS), medium-energy electron diffraction (MEED), Auger electron diffraction (AED), SEELFS, TED and atom diffraction (AD). 

Depth sensitivity is an equally important consideration in the analysis of surfaces. Techniques based on the detection of electrons or ions derive their surface sensitivity from the fact that these species cannot travel long distances in soflds without undergoing interactions which cause energy loss. If electrons are used as the basis of an analysis, the depth resolution will be relatively shallow and depend on both the energy of the incident and detected electrons and on characteristics of the material. In contrast, techniques based on high energy photons such as x-rays will sample a much greater depth due... 

Analysis of Surface Molecular Composition. Information about the molecular composition of the surface or interface may also be of interest. A variety of methods for elucidating the nature of the molecules that exist on a surface or within an interface exist. Techniques based on vibrational spectroscopy of molecules are the most common and include the electron-based method of high resolution electron energy loss spectroscopy (hreels), and the optical methods of ftir and Raman spectroscopy. These tools are tremendously powerful methods of analysis because not only does a molecule possess vibrational modes which are signatures of that molecule, but the energies of molecular vibrations are extremely sensitive to the chemical environment in which a molecule is found. Thus, these methods direcdy provide information about the chemistry of the surface or interface through the vibrations of molecules contained on the surface or within the interface. 

High-Resolution Electron Energy Loss Spectroscopy (HREELS) 1.8.3... 

High-Resolution Electron Energy Loss Spectroscopy... 

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