Photoelectron spectroscopy systems studied

O Dell, C. S., Walker, G. W., Richardson, P. E., 1986. Electrochemistry of the chalcocite-xandiate system. J. Appl. Electrochem., 16 544-554 Opahle, I., Koepemik, K., Eschrig, H., 2000. Full potential band stracture calculation of iron pyrite. Computational Materials Science, 17(2 - 4) 206 - 210 Page, P. W. and Hazell, L. B., 1989. X-ray photoelectron spectroscopy (XPS) studies of potassium amyl xanthate (KAX) adsorption on precipitated PbS related to galena flotation. Inter. J. Miner. Process, 25 87 - 100... 

Elastomers present other complications. They are usually filled systems and although the solid filler does not generally occupy the outermost layers according to the results of several X-ray photoelectron spectroscopy (XPS) studies, they tend to increase the contact angle hysteresis (difference between advancing and receding contact angles, 0 - 0,) which further reduces confidence in the data. A recent study... 

In a carbon-supported metal electrocatalyst, the electronic interaction between metal and carbon support has a significant effect on its electrochemical performance [4], For carbon-supported Pt electrocatalyst, carbon could accelerate the electron transfer at the electrode-electrolyte interface, leading to an accelerated electrode process. Typically, the electrons are transferred from platinum clusters to the oxygen species on the surfece of a carbon support material and the chemical bond formation or the charge transfer process occurs at the contacting phase, which is considered to be beneficial to the enhancement of the catalytic properties in terms of activity and stability of the electrocatalysts. Experimentally, the investigation into the electron interaction between metal catalyst and support materials could be realized by various physical, spectroscopic, and electrochemical approaches. The electron donation behavior of Pt to carbon support materials has been demonstrated by the electron spin resonance (ESR) X-ray photoelectron spectroscopy (XPS) studies, with the conclusion that the electron interaction between Pt and carbon support depends on their Fermi level of electrons. It is considered that the electronic structure change of Pt on carbon support induced by the electron interaction has positive effect toward the enhancement of the catalytic properties and the improvement of the stability of the electrocatalyst system. However, the exact quantitative relationship between electronic interaction of carbon-supported catalyst and its electrocatalytic performance is still not yet fully established [4]. 

Film-forming chemical reactions and the chemical composition of the film formed on lithium in nonaqueous aprotic liquid electrolytes are reviewed by Dominey [7], SEI formation on carbon and graphite anodes in liquid electrolytes has been reviewed by Dahn et al. [8], In addition to the evolution of new systems, new techniques have recently been adapted to the study of the electrode surface and the chemical and physical properties of the SEI. The most important of these are X-ray photoelectron spectroscopy (XPS), SEM, X-ray diffraction (XRD), Raman spectroscopy, scanning tunneling microscopy (STM), energy-dispersive X-ray spectroscopy (EDS), FTIR, NMR, EPR, calorimetry, DSC, TGA, use of quartz-crystal microbalance (QCMB) and atomic force microscopy (AFM). 

Surface composition and morphology of copolymeric systems and blends are usually studied by contact angle (wettability) and surface tension measurements and more recently by x-ray photoelectron spectroscopy (XPS or ESCA). Other techniques that are also used include surface sensitive FT-IR (e.g., Attenuated Total Reflectance, ATR, and Diffuse Reflectance, DR) and EDAX. Due to the nature of each of these techniques, they provide information on varying surface thicknesses, ranging from 5 to 50 A (contact angle and ESCA) to 20,000-30,000 A (ATR-IR and EDAX). Therefore, they can be used together to complement each other in studying the depth profiles of polymer surfaces. 

In addition to the natural improvements expected in the accuracy of the measurements, and the increased scope in the types of systems examined, new techniques go beyond the issue of thermochemistry to allow for very detailed studies of reaction dynamics. The investigation by Zewail and co-workers of the reactivity of planar COT" on the femtosecond time scale is likely only the beginning. Time-resolved photoelectron spectroscopy, for example, has recently been used to map the potential energy surfaces for the dissociation of simple ions IBr and l2. " Although applications in the field of organic reactive molecules are likely far off, they are now possible. 

Photoelectron spectroscopy has been used to determine the threshold of electron detachment in small cluster anions and in some cases electronic transitions may be observed. The group of Nakajima and co-workers (261-264) studied several metal sulfide cluster anions. Many other systems have been studied by photoelectron spectroscopy including the [LaCJ (265), [AuC6F6] (266), and mixed-metal cluster anions (267). 

A series of supported cobalt catalysts (C0/AI2O3, C0/K-AI2O3, C0/S1O2, C0/T1O2) have been examined by X-ray photoelectron spectroscopy (XPS) and microreactor studies. A catalyst treatment system attached to the XPS spectrometer was used to prepare in situ treated (air,... 

Recent studies using high resolution electron energy loss and photoelectron spectroscopy to investigate the effect of sulfur on the CO/Ni(100) system are consistent with an extended effect by the impurity on the adsorption and bonding of CO. Sulfur levels of a few percent of the surface nickel atom concentration were found sufficient to significantly alter the surface electronic structure as well as the CO bond strength. 

Another approach is to perform ex situ reactions and insert the sample into a high vacuum system without exposure to ambient conditions. Incorporating N2 glove boxes or reactor systems with X-ray photoelectron spectroscopy (XPS) sample handling can also provide information that is closer to operational conditions. In a similar manner ex situ reactions and sample handling are starting to be apphed to electron microscopy studies. Commercially available sample transfer systems will accelerate the application of this methodology. 

Mixed valence phenomena, such as studied by photoelectron spectroscopy in lanthanide systems, are expected to become important especially (but not only) in the second half of the actinide series. It is to be expected that much of the photoelectron spectroscopic effort will be in the future devoted to the study of these phenomena in actinides, especially as soon as measurements on hazardous actinides will become more feasible. 

Evidently, adsorption of chemical compounds at gold surfaces via specific Au—S interactions has heen very intensively studied for the last twenty years. In a recent review [90], Vericat et al. have described their own results of electrochemical, in situ STM, X-ray photoelectron spectroscopy (XPS), and SXD studies on adsorption of sulfur on Au(lll). It has been stated that S—Au bonds determine the structure and adsorption/desorption kinetics for both S — Au (111) and alkanethi-olate/Au(lll) systems in NaOH. 

Other techniques such as low-energy electron diffraction (LEED) are also used for surface analysis, primarily for large single crystals. Single crystal metal surfaces have been used to study hydrocarbon catalysis on platinum (Anderson 1975). Techniques such as x-ray photoelectron spectroscopy (XPS) are also used for surface analysis but normally the reports describe mostly idealized single-crystal surfaces in high vacuum as opposed to using real-life (practical) catalyst systems under reaction environments. 

XPS studies in uranyl—quartz systems. Using X-ray photoelectron spectroscopy (XPS), Froideval et al. (2003) found two kinds of pH-dependent uranyl species at high surface... 

The same system, i.e., C2H2 on Pt(l 11) has also been studied by ultraviolet photoelectron spectroscopy (UPS), by high resolution electron energy loss spectroscopy (HREELS), and by thermal desorption spectroscopy (TDS). The authors have all... 

A review of the Journal of Physical Chemistry A, volume 110, issues 6 and 7, reveals that computational chemistry plays a major or supporting role in the majority of papers. Computational tools include use of large Gaussian basis sets and density functional theory, molecular mechanics, and molecular dynamics. There were quantum chemistry studies of complex reaction schemes to create detailed reaction potential energy surfaces/maps, molecular mechanics and molecular dynamics studies of larger chemical systems, and conformational analysis studies. Spectroscopic methods included photoelectron spectroscopy, microwave spectroscopy circular dichroism, IR, UV-vis, EPR, ENDOR, and ENDOR induced EPR. The kinetics papers focused on elucidation of complex mechanisms and potential energy reaction coordinate surfaces. 

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