Auger emission spectrometry

Abbreviations AES, Auger emission spectrometry CRM, Certified reference material DL, Detection limit ED, Energy dispersive ESRF, European Synchrotron Radiation Facility EXAES, Extended X-ray absorption fine structure NEXAFS, Near edge X-ray absorption fine structure PCI, Phase contrast imaging RM, Reference material SR, Synchrotron radiation SRM, Standard reference material TXRF, Total reflection X-ray fluorescence XANES, X-ray absorption near edge structure XAS, X-ray absorption spectrometry XDM, X-ray diffraction microscopy XFCT, X-ray fluorescence computerized microtomography XPEEM, X-ray photoelectron microscopy XPS, X-ray photoelectron spectrometry XRD, X-ray diffraction XRF, X-ray fluorescence... 

Examples of conventional instrumentation used for electron-excited X-ray emission spectroscopy and Auger electron spectrometry are shown in Figures 2 and 3 respectively. Details concerning the instrumentation may be found elsewhere (25-29). 

GD-OES (glow discharge optical emission spectrometry) are applied. AES (auger electron spectroscopy), AFM (atomic force microscopy) and TRXF (transmission reflection X-ray fluorescence analysis) have been successfully used, especially in the semiconductor industry and in materials research. 

Due to relativistic effects important for the inner shells of atoms, the deep ntf shells split in energy according to the j value from the spin-orbit coupling j = t + 1/2. Therefore, deep inner shells are classified by their nfj values. Frequently, in X-ray emission and Auger electron spectrometry, the shell index... 

The surface of the particles can be studied directly by the use of electron microprobe X-ray emission spectrometry (EMP), electron spectroscopy for chemical analysis (ESCA), Auger electron spectroscopy (AES), and secondary ion-mass spectrometry. Depth-profile analysis determines the variation of chemical composition below the original surface. 

AES atomic emission spectrometry Auger emission spectroscopy AF atomic fluorescence AFS atomic fluorescence spectrometry (laser ICP/ICP, HC/ICP, laser/furnace) AIDS acquired immune deficiency syndrome... 

AES Atomic emission spectrometry Auger electron spectroscopy... 

The analysis of metals by X-ray fluorescence has been widely used on geological and sediment samples, either deposited on filters or as thin films. The method can be made quantitative by using geological standards and transition metals can be determined in the 1-5 tg per g range. The surfaces of sediment particles can be examined by the direct use of electron microprobe X-ray emission spectrometry and Auger electron spectroscopy. Although these methods are not particularly sensitive, they can allow the determination of a depth-profile of trace metals within a sediment particle. 

See also Activation Anaiysis Neutron Activation Charged-Particle Activation Photon Activation. Atomic Emission Spectrometry Inductively Coupled Plasma. Atomic Mass Spectrometry Inductively Coupled Plasma. Mass Spectrometry Overview. Surface Analysis Particle-Induced X-Ray Emission Auger Electron Spectroscopy Ion Scattering Nuclear Reaction Analysis and Elastic Recoil Detection. X-Ray Fluorescence and Emission Wavelength Dispersive X-Ray Fluorescence Energy Dispersive X-Ray Fluorescence. 

The elemental composition of the resultant deposits was determined by Auger Electron Spectrometry (AES) with a primary electron beam having an emission current of 1 mA at 3 keV. During analysis, the films were sputtered by a 2 keV Ar beam with a raster area of 2x2 mm. The films were further characterized by means of Fourier Transform Infirared Spectrometry (FTIR), and elliposmetry. 

Spontaneous emission of photons. This process refers to a spontaneous transition of the electron from the excited state 2 to the lower energy state 1 with emission of a photon of frequency vi2 = E2 - Ef jh. This process constitutes the photophysical basis of atomic emission spectrometry, which will be termed here optical emission spectrometry in order to use the acronym OES instead of AES because the latter acronym can be confused with that for Auger electron spectroscopy. 

Acoustic emission Atomic emission detection Analytical electron microscopy (1) Atomic emission spectrometry (2) Auger electron spectroscopy (3) Acoustic emission spectroscopy Acoustic emission technology Atomic force acoustic microscopy... 

Elastic Recoil Detection Analysis Glow discharge mass spectrometry Glow discharge optical emission spectroscopy Ion (excited) Auger electron spectroscopy Ion beam spectrochemical analysis... 

In this chapter, we have chosen from the scientific literature accounts of symposia published at intervals during the period 1920 1990. They are personal choices illustrating what we believe reflect significant developments in experimental techniques and concepts during this time. Initially there was a dependence on gas-phase pressure measurements and the construction of adsorption isotherms, followed by the development of mass spectrometry for gas analysis, surface spectroscopies with infrared spectroscopy dominant, but soon to be followed by Auger and photoelectron spectroscopy, field emission, field ionisation and diffraction methods. 

The different emission products which are possible after photoionization with free atoms lead to different experimental methods being used for example, electron spectrometry, fluorescence spectrometry, ion spectrometry and combinations of these methods are used in coincidence measurements. Here only electron spectrometry will be considered. (See Section 6.2 for some reference data relevant to electron spectrometry.) Its importance stems from the rich structure of electron spectra observed for photoprocesses in the outermost shells of atoms which is due to strong electron correlation effects, including the dominance of non-radiative decay paths. (For deep inner-shell ionizations, radiative decay dominates (see Section 2.3).) In addition, the kinetic energy of the emitted electrons allows the selection of a specific photoprocess or subsequent Auger or autoionizing transition for study. 

For a correct analysis of photoionization processes studied by electron spectrometry, convolution procedures are essential because of the combined influence of several distinct energy distribution functions which enter the response signal of the electron spectrometer. In the following such a convolution procedure will be formulated for the general case of photon-induced two-electron emission needed for electron-electron coincidence measurements. As a special application, the convolution results for the non-coincident observation of photoelectrons or Auger electrons, and for photoelectrons in coincidence with subsequent Auger electrons are worked out. Finally, the convolutions of two Gaussian and of two Lorentzian functions are treated. 

Mdssbauer spectrometry gives information about the chemical environment of the Mdssbauer nuclide in the excited state at the instant of emission of the photon. It does not necessarily reflect the normal chemical state of the daughter nuclide, because of the after-effects that follow the decay of the mother nuclide (recoil and excitation effects, including emission of Auger electrons). At very short lifetimes of the excited state, ionization and excitation effects may not have attained relaxation at the instant of emission of the y-ray photon this results in a time-dependent pattern of the Mdssbauer spectrum. 

Until recently, analytical investigations of surfaces were handicapped by the lack of suitable methods and instrumentation capable of supplying reliable and relevant information. Electron diffraction is an excellent way to determine the geometric arrangement of the atoms on a surface, but it does not answer the question as to the chemical composition of the upper atomic layer. The use of the electron microprobe (EMP), a powerful instrument for chemical analyses, is unfortunately limited because of its extended information depth. The first real success in the analysis of a surface layer was achieved by Auger electron spectroscopy (AES) [16,17], followed a little later by other techniques such as electron spectroscopy for chemical analysis (ESCA) and secondary-ion mass spectrometry (SIMS), etc. [18-23]. All these techniques use some type of emission (photons, electrons, atoms, molecules, ions) caused by excitation of the surface state. Each of these techniques provides a substantial amount of information. To obtain the optimum Information it is, however, often beneficial to combine several techniques. 

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