AEAPS potential spectroscopy

AEAPS Auger electron appearance potential spectroscopy... 

Auger Electron Appearance Potential Spectroscopy (AEAPS)... 

AEAPS Auger Electron Appearance Potential Spectroscopy The EAPFS cross-section is monitored by Auger electron intensity. Also known as APAES. 

There are three main detection modes for EAPFS within the appearance potential spectroscopy (APS) technique./31/ First, one may monitor soft-x-ray emission due to the decay of the core hole left by the primary process. This is called SXAPS-EAPFS (Figure le). Second, it is also possible to monitor Auger electrons due to the same core-hole decay, as in AEAPS-EAPFS and AMEFS-EAPFS, cf. Figure If. Third, one may measure the remaining total intensity of... 

Appearance potential spectroscopy involves detection of electronic transitions not of the backscattered electrons as in ELS, but of secondary processes. The latter include increase in soft X-ray (SXAPS) or Auger electron (AEAPS) emission or decrease in elastically scattered primary electrons (DAPS) (382). SXAPS is not as sensitive as AES for surface chemical analysis. However, SXAPS and IS spectra are easier to analyze than AES, since only one core transition is involved. This makes SXAPS and IS quite convenient for detecting heavy elements on catalyst surfaces. 

Appearance potential spectroscopies (SXAPS, AEAPS, DAPS, TCS, XEAPS, EAPFS, lETS)... 

AEAPS Auger Electron Appearance Potential Spectroscopy, 2 AEES Nuclear Auger Electron (Emission) Spectroscopy ... 

Figure 1 A schematic diagram showing energy levels involved in techniques used to probe unoccupied density of states of a metai. XAS, X-ray absorption spectroscopy BIS, Bremsstrahlung isochromat spectroscopy I PE, inverse photoemission DAPS, disappearance potentiai spectroscopy SXAPS, soft X-ray appearance potentiai spectroscopy and AEAPS, Auger electron appearance potential spectroscopy.

Figure 7 Normalized chromium La.a level AEAPS spectra for the CrN films and elemental chromium. The emission current was 2 mA and the modulation voltage was 1 Vp p. The strength of the signal (i.e., the density of unoccupied states at the Fermi level) is more for the films. (Reproduced with permission from Chourasia AR and Hood SJ (2001) Auger electron appearance potential spectroscopy. Surface and Interface Analysis 31 291-296 John Wiley and Sons Ltd.)...

Disappearance Potential Spectroscopy. Crossing an ionization threshold means that electrons are lost from the primary beam as a result of ionization of a core hole. Thus if the reflected current of electrons at the primary energy, more usually termed the elastically reflected current, is monitored as a function of energy, it should show a sharp decrease as a threshold is crossed. This is the principle of operation of DAPS. It is in a sense the inverse of AEAPS, and indeed if spectra from the two techniques from the same surface are compared, they can be seen to be mirror images of each other. Background problems occur also in DAPS,... 

Appearance potential auger electron spectroscopy. See AEAPS. 

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