Quantitative X-ray photoelectron spectroscopy

Matrix effects, which are somewhat stronger in comparison to those in quantitative X-ray photoelectron spectroscopy, mostly originate from the backscatter effect. Many of the parameters mentioned above are difficult to determine. Therefore, in practical quantitative AES empirical relative sensitivity factors (RSFs) are used and the concentration Q (at%) of element i in the thin AES analytical volume is derived for a certain matrix from measurements of the intensities measured for element i, and all elemental constituents j by... 

Zielke et al. [83] concluded that neither temperature-programmed desorption of functional groups nor quantitative X-ray photoelectron spectroscopy can give absolute information about the exterior surface functionalities on a fiber surface, because both techniques include subsurface contributions. Interactions between the functionalities on the outer fiber surface and test liquids (including aqueous solutions with varying pH values), however, affect the measurable contact angles [85]. 

X-rays provide an important suite of methods for nondestmctive quantitative spectrochemical analysis for elements of atomic number Z > 12. Spectroscopy iavolving x-ray absorption and emission (269—273) is discussed hereia. X-ray diffraction and electron spectroscopies such as Auger and electron spectroscopy for chemical analysis (esca) or x-ray photoelectron spectroscopy are discussed elsewhere (see X-raytechnology). 

In other articles in this section, a method of analysis is described called Secondary Ion Mass Spectrometry (SIMS), in which material is sputtered from a surface using an ion beam and the minor components that are ejected as positive or negative ions are analyzed by a mass spectrometer. Over the past few years, methods that post-ion-ize the major neutral components ejected from surfaces under ion-beam or laser bombardment have been introduced because of the improved quantitative aspects obtainable by analyzing the major ejected channel. These techniques include SALI, Sputter-Initiated Resonance Ionization Spectroscopy (SIRIS), and Sputtered Neutral Mass Spectrometry (SNMS) or electron-gas post-ionization. Post-ionization techniques for surface analysis have received widespread interest because of their increased sensitivity, compared to more traditional surface analysis techniques, such as X-Ray Photoelectron Spectroscopy (XPS) and Auger Electron Spectroscopy (AES), and their more reliable quantitation, compared to SIMS. 

X-ray photoelectron spectroscopy (XPS) electron spectroscopy for chemical analysis (ESCA) X-rays electrons 5nm yes quantitative 10 pm (scanning) >10 pm surface composition... 

X-ray photoelectron spectroscopy (XPS), which is synonymous with ESCA (Electron Spectroscopy for Chemical Analysis), is one of the most powerful surface science techniques as it allows not only for qualitative and quantitative analysis of surfaces (more precisely of the top 3-5 monolayers at a surface) but also provides additional information on the chemical environment of species via the observed core level electron shifts. The basic principle is shown schematically in Fig. 5.34. 

X-ray photoelectron spectroscopy (also called electron spectroscopy for chemical analysis, or ESCA) is a surface technique that can be used to detect elements qualitatively (and quantitatively, in some cases) in the surface layers of solids, as well as the chemical states (species) of the elements. The basic experimental apparatus for performing XPS studies includes an x-ray source (most commonly,... 

The primary techniques used in this study include X-ray photoelectron spectroscopy (XPS), reflection-absorption infrared spectroscopy (RAIR), and attenuated total reflectance infrared spectroscopy (ATR). XPS is the most surface-sensitive technique of the three. It provides quantitative information about the elemental composition of near-surface regions (< ca. 50 A sampling depth), but gives the least specific information about chemical structure. RAIR is restricted to the study of thin films on reflective substrates and is ideal for film thicknesses of the order of a few tens of angstroms. As a vibrational spectroscopy, it provides the type of structure-specific information that is difficult to obtain from XPS. The... 

As a surface analytical tool, SIMS has several advantages over X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES). SIMS is sensitive to all elements and isotopes in the periodic table, whereas XPS and AES cannot detect H and He. SIMS also has a lower detection limit of 10 5 atomic percent (at.S) compared to 0.1 at.S and 1.0 at.% for AES and XPS, respectively. However, SIMS has several disadvantages. Its elemental sensitivity varies over five orders of magnitude and differs for a given element in different sample matrices, i.e., SIMS shows a strong matrix effect. This matrix effect makes SIMS measurements difficult to quantify. Recent progress, however, has been made especially in the development of quantitative models for the analysis of semiconductors [3-5]. 

These sites can be studied by electron paramagnetic resonance (EPR), ultraviolet (UV) spectrometry, x-ray photoelectron spectroscopy (XPS), and other methods. Besides, a quantitative study of redox sites can be carried out with the help of a volumetric or gravimetric study of the adsorption of the oxidizing or the reducing molecules. 

Copper-containing molecular sieve materials are very important catalysts in many liquid-phase oxidation reactions. The analysis of metal content is usually obtained using atomic absorption spectroscopy (AAS) but this provides no information on the distribution of the metal within the material. In this paper, we report on the characterisation of a siliceous MCM 41 material postmodified with a Schiff base copper complex by x-ray photoelectron spectroscopy (XPS), AAS and other standard techniques. Quantitative estimations of the copper concentrations and chemical states and its distribution within the material have been made using XPS. The effect of modification by the Schiflf base copper complex on the surface characteristics of the MCM 41 was investigated by nitrogen sorption at 77 K. 

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