Auger electron spectroscopy fine structures

All analytical methods that use some part of the electromagnetic spectrum have evolved into many highly specialized ways of extracting information. The interaction of X-rays with matter represents an excellent example of this diversity. In addition to straightforward X-ray absorption, diffraction, and fluorescence, there is a whole host of other techniques that are either directly X-ray-related or come about as a secondary result of X-ray interaction with matter, such as X-ray photoemission spectroscopy (XPS), surface-extended X-ray absorption fine structure (SEXAFS) spectroscopy, Auger electron spectroscopy (AES), and time-resolved X-ray diffraction techniques, to name only a few [1,2]. 

Spectroscopy produces spectra which arise as a result of interaction of electromagnetic radiation with matter. The type of interaction (electronic or nuclear transition, molecular vibration or electron loss) depends upon the wavelength of the radiation (Tab. 7.1). The most widely applied techniques are infrared (IR), Mossbauer, ultraviolet-visible (UV-Vis), and in recent years, various forms ofX-ray absorption fine structure (XAFS) spectroscopy which probe the local structure of the elements. Less widely used techniques are Raman spectroscopy. X-ray photoelectron spectroscopy (XPS), secondary ion imaging mass spectroscopy (SIMS), Auger electron spectroscopy (AES), electron spin resonance (ESR) and nuclear magnetic resonance (NMR) spectroscopy. 

XRF = X-ray fluorescence spectroscopy, XPS = X-ray photoelectron spectroscopy, AES = Auger electron spectroscopy, XANES = X-ray absorption near edge spectroscopy, RAIR = Reflectance-absorbance infrared spectroscopy, EXAFS = X-ray absorption fine-structure spectroscopy, ECR = Electric contact resistance, NMR = Nuclear magnetic resonance spectroscopy, IPS = Imaging photoelectron spectromicroscopy. 

Electrons Auger Electron Spectroscopy, Extended X-Ray Absorption Fine Structure, Low-Energy Electron Diffraction, Scanning Electron Microscopy, Surface Extended X-Ray Absorption Fine Structure, Ultraviolet Photoelectron Spectroscopy, X-Ray Absorption Near Edge Fine Structure, and X-Ray Photon Spectroscopy. 

Technique abbreviations AES = Auger Electron Spectroscopy EXAFS = Extended X-Ray Absorption Fine Structure ISS = Ion Scattering Spectroscopy SIMS = Secondary Ion Mass Spectroscopy UPS = Ultraviolet Photoelectron Spectroscopy XANES = X-Ray Absorption Near Edge Structure XPS (or ESCA) = X-Ray Photoelectron Spectroscopy bAnalysis type C = chemical, E = elemental... 

Acronyms abound in photoelectron and related spectroscopies but we shall use only XPS, UPS and, in Sections 8.2 and 8.3, AES (Auger electron spectroscopy), XRF (X-ray fluorescence) and EXAFS (extended X-ray absorption fine structure). In addition, ESCA is worth mentioning, briefly. It stands for electron spectroscopy for chemical analysis in which electron spectroscopy refers to the various branches of spectroscopy which involve the ejection of an electron from an atom or molecule. However, because ESCA was an acronym introduced by workers in the field of XPS it is most often used to refer to XPS rather than to electron spectroscopy in general. 

The third problem also concerns the choice of whether to leave out certain material. In a book of this size it is not possible to cover all branches of spectroscopy. Such decisions are difficult ones but I have chosen not to include spin resonance spectroscopy (NMR and ESR), nuclear quadrupole resonance spectroscopy (NQR), and Mossbauer spectroscopy. The exclusion of these areas, which have been well covered in other texts, has been caused, I suppose, by the inclusion, in Chapter 8, of photoelectron spectroscopy (ultraviolet and X-ray), Auger electron spectroscopy, and extended X-ray absorption fine structure, including applications to studies of solid surfaces, and, in Chapter 9, the theory and some examples of lasers and some of their uses in spectroscopy. Most of the material in these two chapters will not be found in comparable texts but is of very great importance in spectroscopy today. 

Surface analytical techniques such as Auger electron spectroscopy (27), X-ray photoelectron spectroscopy (28), and secondary-ion mass spectrometry (29) have been used to study LB films. Synchrotron radiation is a particularly powerful probe enabling X-ray near-edge structure and extended X-ray absorption fine structure to be measured. Angle-resolved photoemission studies (30) confirmed the existence of a one-dimensional energy band along the (CH2)jc chain in a fatty acid salt film. 

Recently, new instrumental techniques have become available for determining surface structures on an atomic scale. These include X-ray fine structure (EXAFS), electron spectroscopies, ultraviolet photoelectron spectroscopy (UPS), X-ray photoelectron spectroscopy (XPS), Auger electron spectroscopy (AES), ion spectroscopies, secondary-ion... 

Structure of Active Sites. - Klier and others have claimed that the active phase is a Cu" species dissolved in ZnO. Estimating the amount of dissolved Cu" reflected irreversible chemisorption of CO in proportion to the dissolved Cu" ". The existence of Cu in the active state is verified by means of Auger electron spectroscopy (AES), X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS), but it is also pointed out that the Cu" concentration depends upon the total content of Cu in the catalyst. 

XANES) AES fine structure Auger electron spectroscopy Yes 0,223-227 ... 

Auger electron appearance potential spectroscopy Auger electron spectroscopy Atomic force microscopy Azimuthal photoelectron diffraction Appearance potential spectroscopy Angle-resolved Auger electron spectroscopy Angle-resolved photoemission extended fine structure... 

A wide variety of other techniques are available for the characterization of supported catalyst systems including X-ray absorption fine structure (EXAFS), Mossbauer, Auger electron. X-ray, and u.v. spectroscopies, magnetic susceptibilities, electron spin resonance spectroscopy, and transmission electron microscopy. However these techniques have not been employed to any significant effect. 

---