Interatomic Auger Transitions Research Articles

Search for the interatomic Auger effect in Nitrous Oxide

The interatomic Auger effect following O 1s ionization in N2O has been experimentally investigated using multi-electron coincidence spectroscopy. The expected transition energies have been established by comparison to the measured N 1s−1v−1 core-valence double ionization energies. We describe a procedure to eliminate the background of two competing processes contributing spectroscopic signatures to the same energy range, namely double Auger decay of the O 1s vacancy and direct single-photon double ionization into the N 1s−1v−1 states. While the interatomic Auger transitions could not be successfully isolated, we provide an upper boundary of the transition probability of 0.07% with respect to the dominant single Auger decay after O 1s ionization.

Resonance Interatomic Auger Transitions

The interatomic Auger transitions in compounds containing atomic components with core levels close in energy are studied theoretically and experimentally. The Coulomb transitions of holes between such levels lead to resonant enhancement of the Auger spectra (with respect to the energy difference between the levels). Interatomic Auger transitions involving higher levels are formed by shaking up electrons due to the dynamic field of photo-holes produced in the process of absorbing X-ray radiation and during the transition. These effects are observed experimentally in the XPS and Auger spectra of CuInSe2-type materials.

Resonant Interatomic Auger Transition in Chalcopyrite CuInSe2

The interatomic Auger transitions in compounds containing atomic components with core levels close in energy are studied theoretically and experimentally. The Coulomb transitions of a hole between such levels lead to a resonant enhancement of the Auger spectra (with respect to the energy difference between the levels). Interatomic Auger transitions involving high lying levels are formed by shaking up electrons due to the dynamic field of photo holes produced during the transition. These effects are observed experimentally in XPS and Auger spectra of CuInSe2 type materials.

Effect of residual oxygen on ionization processes of Si + and Si 2+ sputtered from Si(1 1 1)-7 × 7 surface

The effect of residual oxygen impurity on ionization processes of Si + and Si 2+ has been studied quantitatively. In this study, ion sputtering experiments were carried out for a Si(1 1 1)-7 × 7 surface, irradiated with 9–11 keV Ar 0 and Kr 0 beam. Even if the oxygen concentration is less than the detection limit of Auger electron spectrometry, SiO + and SiO 2 + ions have been appreciably observed. Moreover, as the SiO + and SiO 2 + yields increases, the Si + yield is slightly enhanced, whereas the Si 2+ yield is significantly reduced. From the incidence angle dependence of secondary ion yields, it is confirmed that Si +* (Si + with a 2p hole) created in the shallow region from the surface exclusively contributes to Si 2+ formation. By assuming that the SiO + and SiO 2 + yields are proportional to the residual oxygen concentration, these observations are reasonably explained: The increase of Si + with the increase of residual oxygen is caused by a similar effect commonly observed for oxidized surfaces. The decrease of Si 2+ yield can be explained by the inter-atomic Auger transition between the residual oxygen impurity and Si +*, which efficiently interferes the Si 2+ formation process.

Interatomic Auger decay in CO molecule

Energy spectra of electrons ejected in electron impact on CO molecules have been measured for the incident electron energy 1400 eV. The aim was to study the interatomic Auger transitions resulted from the filling in the O K-shell hole by a C K-shell electron. The corresponding peaks have been identified and their relative transition probabilities (partial widths) measured. Theoretical widths of these transitions calculated in the Hartree–Fock approximation are in good agreement with the experimental data.

Effect of residual oxygen in Si(1 1 1)-7 × 7 surface on Si+ and Si2+ sputter yields

Effect of the residual oxygen impurity on the secondary ion yields in the sputtering from the Si(111)-7×7 surface bombarded by the 11keV Ar0 neutral beam has been studied with use of a time-of-flight technique. Even if the oxygen concentration is much less than the detection limit of the present Auger electron spectrometer, not only Si+ and Si2+ ions but also SiO+ and SiO2+ ions have been significantly detected. As the oxygen ion yield, estimated from SiO+ and SiO2+ signals, increases, the Si+ yield is enhanced, whereas the Si2+ yield is reduced. The enhancement of the Si+ yield may be ascribed to the large electron affinity of O in comparison to that of Si, while the decrease in the Si2+ yield could be explained in terms of the inter-atomic Auger transition between O and one of the precursors for Si2+ (viz. an excited Si+ with a 2p hole, Si+∗), which efficiently interferes with the production of Si2+.

A metastable-induced electron spectroscopy study on the process of oxygen adsorption at a Ni(1 1 0) surface

The electronic structure of oxygen-adsorbed Ni(110) surfaces has been studied by metastable-induced electron spectroscopy (MIES). Helium metastable atoms are de-excited both at clean and at oxygen-adsorbed Ni(110) surfaces through the process of resonance ionization followed by Auger neutralization (AN). The intensity of electron emission due to AN was increased by lower exposures of oxygen (∼0.5l), which is attributed to an enhanced contribution of sp-state electrons at the Ni surface to the AN process. At moderate exposures of oxygen (1–3l) where the low-energy electron diffraction (LEED) pattern showed (2×1 ) reconstruction, the MIES spectra exhibited an O 2p-induced peak, caused by inter-atomic Auger transition between O 2p and Ni 3d states. With increasing exposure to 4l, the LEED pattern changed to (3×1 ), while the O 2p-induced peak position moved to lower energies. Variations in the local electronic structure of oxidized top-layers of the Ni(110) surface and the process of metastable-induced electron emission are discussed in connection with the oxygen-induced structural change.

Deconvolution of Auger electron spectra of hyperthermal highly charged ions at metal surfaces

Using a Monte Carlo simulation of electron scattering near the jellium edge of metals, we investigate the spectra of energy loss of Auger electrons emitted in regions around the jellium edge. A deconvolution procedure allows to remove this background from the experimental Auger spectra, in order to restore them without energy losses. This procedure is applied to Auger spectra from H-like and metastable He-like highly charged ions and from Ar 9+ and metastable Ar 8+ impinging with very low energy on metal surfaces. The deconvoluted spectra unveal for the first time inter-atomic Auger transitions between the highly charged ions and target atoms.

Experimental interatomic Auger rates in sodium halides.

Interatomic Auger transition rates of holes in the two outermost alkali-metal ion core levels have been measured in the sodium halides. The Na 2s core hole, which decays via a singly interatomic Coster-Kronig process, has a lifetime width of 0.75\ifmmode\pm\else\textpm\fi{}0.15, 0.45\ifmmode\pm\else\textpm\fi{}0.10, and 0.46\ifmmode\pm\else\textpm\fi{}0.10 eV in NaF, NaCl, and NaBr, respectively. The 2p hole, which decays via a doubly interatomic process, has a lifetime width of 0.10\ifmmode\pm\else\textpm\fi{}0.05 and 0.06 eV in NaF and NaCl, respectively. The large phonon broadenings determined here, ranging from 0.7 to 1.0 eV in the different sodium halides, are in excellent agreement with calculated values and are responsible for the large uncertainty limits on the determined lifetimes. The absolute values of the Na 2s and 2p lifetime widths are comparable to those from theoretical calculations.

Secondary ion emission from lithium fluoride under impact of slow multicharged ions

Secondary ion emission has been investigated for bombardment of polycrystalline lithium fluoride by slow multicharged Ar ions (charge state q ≤ 9, impact energy E k ≤ 500 eV). The F − ions originate from collisional energy transfer, almost independent of the primary ion charge, whereas the F + yield strongly increases with q. The F + ions are produced via interatomic Auger transitions from the F − 2p valence band into projectile states, and their desorption from LiF is controlled by Coulomb interaction of F + with Li + and F − surface ions, and LiF lattice relaxation. At high impact energy, emission of Li + is also mainly due to collisional energy transfer, but toward lower E k the primary ion charge plays an increasingly important role. The present measurements demonstrate that secondary ions account for less than 0.1% of our earlier measured total sputter yields from LiF.

Electron-stimulated desorption of Kr 2+ from the surface of solid Kr

We have observed that electronic excitations of condensed Kr by low-energy electron impact resulted in the desorption of Kr +, Kr 2+, Kr 3+, and Kr + 2 from the surface of solid Kr. The measurement of the impact energy dependence of Kr 2+ desorption yields showed a threshold at an impact energy of 83 eV and the yield increased drastically at an impact energy between 100 and 120 eV. By referring to the excitation energy in the gas phase, these energies can be attributed to 4p -3 (triple), 3d -1 (inner shell), 3d -14p -1n l (shake up), and 3d -14p -1 (shake off) Kr atom ionizations. The results suggest that these Kr atom ionization processes are the primary excitation leading to the desorption of Kr 2+ from the surface. The onsets of the desorption at the shake ionization energies were significant. We concluded that the interatomic Auger transition between a primarily excited atom and a neighbor neutral which follows 3d shake ionization of Kr plays an important role in the desorption process of Kr 2+.

Electron stimulated desorption of positive and negative ions from [formula omitted] surfaces

We have examined the role of core-hole excitations in electron stimulated desorption (ESD) of positive and negative hydrogen and oxygen ions from SiO 2 Si surfaces. Thresholds observed for positive ion emission at electron energies above 100 eV are correlated with core-level binding energies of substrate atoms and explained in terms of interatomic Auger transitions. Desorption of negative ions closely follows threshold behaviour of corresponding positive ions; it is explained in terms of a charge exchange process in which the outgoing positive ions (or neutrals) capture electrons in the surface region and desorb as negative ions.

Analysis of oxygen binding-energy variations for BaO on W

Interatomic Auger analyses have been made of different forms of BaO layers on W substrates. Variations in Auger spectroscopy energies of the Ba4dBa5pO2p interatomic Auger transition were found to be largely governed by the O2p binding energy of the BaO adsorbate. This was illustrated by comparing results of the Auger data values with values derived from O2p binding energies using ultraviolet photoelectron spectroscopy. Very good agreement was observed not only for the W〈100〉 substrate but also for the W〈110〉 substrate which showed two oxygen-induced electronics state. Variations in binding energy were noted for different states of BaO lattice formation and for different amounts of oxidation, ranging from the transition of Ba to BaO and continuing to the BaO 2 stoichiometry and beyond. Effects were also reported for adsorbate alignment and thermal activation (i.e., reduction) of the oxidized state. An empirical relationship was found suggesting that the more tightly bound the O2p states of the BaO adsorbate were, the lower its work function would be. This link between binding energy and work function was observed to be valid not only for cases of poisoning by oxidation, but held as well during reactivation by the subsequent reduction of the oxide. In addition, this relationship also appeared to predict the low work function obtained through the introduction of substances such as Sc to the BaO-W system. Possible qualitative reasons which might contribute to this are discussed in terms of enhanced dipole effects and shifts in band structure.

The Role of Inter-Atomic Transitions in AES

Experimentally recorded Auger lineshapes suggest that Auger Electron Spectroscopy (AES) can probe a local or a Mulliken like electron distribution, depending on the material examined. The Mulliken electron distribution is especially observed in compound materials. This distribution can be regarded as an approximation of inter-atomic Auger transitions. For a clean silicon surface on the other hand, a local electron distribution suffices to explain the measured Si LVV lineshape. Inter-atomic transitions are in this case not neglected, but incorporated by taking all the different atoms in the surface area, which are of the same element, into account in the calculation.

The influence of inter-atomic transitions in Auger valence band spectroscopy: oxygen on Si(001)2 × 1

In this paper we will show that the description of an Auger process in terms of a process confined to one atom is in general not adequate and the Mulliken population is only in very specific cases a good alternative in evaluating the strength of inter-atomic transitions. The ionicity of the chemical bond cannot be used as a direct measure of the contribution of inter-atomic Auger transitions, as will be demonstrated in the case of the oxygen KVV Auger transitions in gaseous molecular oxygen and oxygen chemisorbed on the Si(001) surface. A full evaluation of inter-atomic transition rates shows that their strength depends on the inter-atomic distance as well as on the screening of the initial core hole.

A soft X-ray study of the interaction of oxygen with Li

We have investigated the interaction of oxygen with a Li multilayer, using photoemission, soft X-ray excited Auger, and Li K-edge photoabsorption. Two phases of Li oxide are suggested. The first phase attains an approximate stoichiometry of “Li 2O x ” where x is 0.76 to 1.26, before a di-oxygen phase starts to form. The di-oxygen has an O-O bond length increased from that of gaseous O 2 and does not seem to exist as the peroxide ion O − 2. Oxygen decreases the p-like density of states near the Fermi level, and the Li K-edge absorption shows two shape resonances due to Li 2p-O 2p and Li 3p-O 2p orbitals. Assignments are made for the inter-atomic Auger transitions induced by the Li 1s hole, with the aid of the observed photoemission energy levels. A short comparison with a Li-S surface is made.

Surface characterization of BaO on W: II. Impregnated cathodes

Analyses of interatomic and valence Auger transitions have been applied to study the surface composition of W based impregnated cathodes. Results show generally a good agreement between calculations based on a linear combination of various calibrated surface components and actual experimental values. Beside Auger peak height analyses, shifts in Auger energy of the interatomic transitions were also used to characterize changes in surface chemistry. Surface compositional changes are illustrated during: Thermal activation; variations in surface composition due to high temperature operation; adlayer depletion due to sputtering; changes occurring during adsorption as well as desorption of gases such as H 2O, O 2 and CO 2.

The bonding state of nitrogen segregated on Fe(100) and on iron nitrides Fe 4N and Fe 2N

X-ray and ultraviolet photoelectron (XPS, UPS) and electron excited Auger electron (AES) spectroscopic studies were performed on nitrogen segregated on Fe(100) and on iron nitride films. The iron-nitrogen bond in both cases is characterized by a single bonding state and a transfer of electron charge from iron to nitrogen atoms, which is more pronounced in the case of the segregated nitrogen. In the N(KLL) spectra, interatomic Auger transitions are observed, both for segregated and the nitridic species.

ChemInform Abstract: Metal‐Support Interaction and Interatomic Auger Transitions in Vapor‐Deposited Molybdenum on Silica and α‐Al2O3

ChemInformVolume 19, Issue 36 Physical Inorganic Chemistry ChemInform Abstract: Metal-Support Interaction and Interatomic Auger Transitions in Vapor-Deposited Molybdenum on Silica and α-Al2O3 A. KATRIB, A. KATRIB Lab. Catal. Chim. Surf., CNRS, Univ. Louis Pasteur, 67070 Strasbourg, Fr.Search for more papers by this authorC. PETIT, C. PETIT Lab. Catal. Chim. Surf., CNRS, Univ. Louis Pasteur, 67070 Strasbourg, Fr.Search for more papers by this authorP. LEGARE, P. LEGARE Lab. Catal. Chim. Surf., CNRS, Univ. Louis Pasteur, 67070 Strasbourg, Fr.Search for more papers by this authorL. HILAIRE, L. HILAIRE Lab. Catal. Chim. Surf., CNRS, Univ. Louis Pasteur, 67070 Strasbourg, Fr.Search for more papers by this authorG. MAIRE, G. MAIRE Lab. Catal. Chim. Surf., CNRS, Univ. Louis Pasteur, 67070 Strasbourg, Fr.Search for more papers by this author A. KATRIB, A. KATRIB Lab. Catal. Chim. Surf., CNRS, Univ. Louis Pasteur, 67070 Strasbourg, Fr.Search for more papers by this authorC. PETIT, C. PETIT Lab. Catal. Chim. Surf., CNRS, Univ. Louis Pasteur, 67070 Strasbourg, Fr.Search for more papers by this authorP. LEGARE, P. LEGARE Lab. Catal. Chim. Surf., CNRS, Univ. Louis Pasteur, 67070 Strasbourg, Fr.Search for more papers by this authorL. HILAIRE, L. HILAIRE Lab. Catal. Chim. Surf., CNRS, Univ. Louis Pasteur, 67070 Strasbourg, Fr.Search for more papers by this authorG. MAIRE, G. MAIRE Lab. Catal. Chim. Surf., CNRS, Univ. Louis Pasteur, 67070 Strasbourg, Fr.Search for more papers by this author First published: September 6, 1988 https://doi.org/10.1002/chin.198836005Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume19, Issue36September 6, 1988 RelatedInformation

Metal-support interaction and interatomic Auger transitions in vapor-deposited molybdenum on silica and .alpha.-alumina

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMetal-support interaction and interatomic Auger transitions in vapor-deposited molybdenum on silica and .alpha.-aluminaAli Katrib, C. Petit, P. Legare, L. Hilaire, and G. MaireCite this: J. Phys. Chem. 1988, 92, 12, 3527–3531Publication Date (Print):June 1, 1988Publication History Published online1 May 2002Published inissue 1 June 1988https://doi.org/10.1021/j100323a041RIGHTS & PERMISSIONSArticle Views65Altmetric-Citations8LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (532 KB) Get e-Alerts