X-ray-excited Auger and photoelectron spectroscopy

Abstract

This article reviews developments in the understanding of x-ray-excited Auger and photoelectron spectra in the light of theoretical developments in atomic, molecular and solid-state physics. After reviewing progress in XPS and AES separately emphasis is placed on the inter-relationship between the two fields: Auger rates, for example, are the dominant contribution to core-level XPS linewidths and by combining XPS and AES it is possible to deduce information about Coster-Kronig processes which are difficult to study directly.An account is given of how the combination of measurements of environmentally dependent shifts in XPS and AES energies allows one to isolate intial-and final-state contributions which can then be related to the results of other experimental techniques.There is a brief discussion of many-electron effects which, in some instances, dominate both XPS and AES spectra.Finally we discuss how the combination of XPS and AES spectra involving valence levels enables one to study the effects of hole-state localisation.

The Development of Auger Spectroscopy as a Probe of Local Electronic Structure

“…For all three elements k was found to depend on the valence charge q, a result found earlier by Snyder [45], and on the number of core holes, N. Saethre, Siggel and Thomas [46] came to similar conclusions from an analysis of molecular charge distributions. We can thus express k in (6) (12) have been applied to the free atom to elemental metal Auger parameter shifts for Na, Mg and Zn and the results obtained for the effects of compression of the valence charge, on-site screening of core-holes and the magnitude of valence charges are all consistent with expectations [47].…”

“…For many years following Auger's discovery technical limitations impeded the development of electron spectroscopy and information about Auger processes was principally obtained indirectly through the study of X-rays [2]. Extensive direct studies of Auger spectra only became possible following the development of high resolution electron spectrometers and ultra high vacuum techniques in the 1960's [3,4] and from then on Auger spectroscopy developed alongside X-ray photoelectron spectroscopy (XPS) [5,6].…”

“…Recently the parameterised forms of the atomic potentials, (6) and (10), of the first and second row elements have been evaluated and used to derive a new scale of electronegativity [48]. The results are shown in Figure 1 and yield an approximately linear relationship across each period when compared with Pauling's original scale [49].…”

Erratum to: “Development of a Super-Stable Datum Point for Monitoring the Energy Scale of Electron Spectrometers in the Energy Range up to 20 keV” by D. Vénos, M. Zbořil, J. Kašpar, O. Dragoun, J. Bonn, A. Kovalík, O. Lebeda, N. A. Lebedev, M. Ryšavý, K. Schlösser, A. Špalek, and Ch. Weinheimer, Vol. 53, No. 3, pp. 305–312, July, 2010

“…This energy shift, which is called a chemical shift, amounts to ±7 eV and is highly correlated with the valence state of the radiating atom [13][14][15]. It is also well known that the binding energies of the electrons in solids, as a rule, are 2-10 eV less than those for free atoms [16,17], while for atoms adsorbed on the surface of solids the binding energies are 1-3 eV less than those for free atoms [18][19][20].…”

Relationship between the Auger line shape and the electronic properties of graphite

“…The use of detailed Auger spectral lineshape analysis to obtain local electronic structure information has had increased emphasis over the past few years, as is evident from the number of recent review articles devoted to this subject (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20). This interest stems from the local nature of the Auger process which has as its initial state a missing core electron.…”