Analyzers, electron energy

Xps ndAes Instrumentation. The instmmentation required to perform xps and aes analyses is generally sophisticated and expensive (19). The need for UHV conditions in order to retain surface cleanliness for a tractable period of time was mentioned above. Beyond this requirement (and the hardware that accompanies it), the most important components of an electron spectrometer system are the source, the electron energy analyzer, and the electron detector. These will be discussed in turn below. 

Microareas By Electron Energy Analyzer , JEOL NeWs 12e (1), 18-22 (1974) 58) Anon,... 

Electron energy analyzer, 24 102—103 Electron energy levels, 21 295 Electron energy loss spectroscopy (EELS), 16 489 24 14 Electroneutrality, 9 613... 

The resolution of overlapping spectral peaks depends on their separations, intensities, and widths. Whereas separation and intensity are predominantly functions of the sample, peak width is strongly influenced by the instrument s design. The observed line is a convolution of the natural line, a function characteristic of inelastically scattered electrons that produces a skewed base line, and the instrument function. The instrument function is, in turn, the convolution of the x-ray excitation line shape, the broadening inherent in the electron energy analyzer, and the effect of electrical filtering. This description is summarized in Table I. 

In 1979, the construction of an XPS system for the investigation of solids in gas atmospheres at pressures of up to 1 mbar was reported by Joyner and Roberts (1979a) this was later commercialized. One differential pumping stage around the high-pressure sample cell was used in combination with the commercial hemispherical electron energy analyzer ESCALAB of V.G. Scientific Ltd. Two "high-pressure" spectrometers of this type were supplied to the University of Wales (Cardiff, UK) and the Boreskov Institute of Catalysis (Novosibirsk, Russia). 

The kinetic energy of the ejected electrons is measured by an electron energy analyzer. The original binding energy B experienced by the electron in the sample can be calculated from using the simple relationship... 

Our earliest alkali halide studies were performed with cesium halides, since the prevailing evidence (Table I) indicated that the vapor would be predominantly monomeric, and hence simplest to interpret. The apparatus employed for these studies (Figure 1) consisted of a cylindrical mirror electron energy analyzer, a non-inductively wound oven for generating the cesium halide vapor, and a helium resonance lamp. The spectra we obtained ( ) for the cesium halides are displayed in Figure 2. They reveal a clearly resolved doublet for Csl, a partially resolved doublet for CsBr, and broad single peaks for CsCl and CsF. We shall briefly reproduce here the arguments we used to interpret these spectra. 

Figure 1. Cylindrical mirror electron energy analyzer (2> ).

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