Lineshapes in core-level photoemission from metals: I. Theory and computational analysis

Hughes, H. P.; Scarfe, J A

doi:10.1088/0953-8984/8/10/014

Cited by 25 publications

(25 citation statements)

References 19 publications

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“…52 Core-level line shapes of metallic TMDC's have been successfully modeled by taking into account the conduction electron screening response and the finite core-hole lifetime. [53][54][55][56] It is clear from Fig. 4 that, in addition to its 0.8-eV spin-orbit splitting, the Se 3d line shape is asymmetric with a characteristic ''metallic'' tail already for pure VSe 2 , and the line shape becomes even more asymmetric as the sample is intercalated with Na.…”

Section: B Core-level Screeningmentioning

confidence: 96%

Electronic structure of pure and alkali-metal-intercalatedVSe2

et al. 1998

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The valence bands of the layered compound VSe 2 and the related intercalation compounds Na x VSe 2 , K x VSe 2 , and Cs x VSe 2 have been investigated by means of angle-resolved photoelectron spectroscopy, and compared to self-consistent linear augmented plane-wave ͑LAPW͒ band calculations. The intercalation compounds were prepared in situ by deposition of Na, K, and Cs on VSe 2 cleavage surfaces. The intercalation was monitored by core-level spectroscopy, and although K was found to intercalate more slowly than Na and Cs, estimated alkali concentrations of xϭ0.2-0.3 were reached for all three alkali metals. Additional depositions mainly seemed to increase the intercalation depth. Good agreement between LAPW calculations and valenceband spectra was found, in particular for the dispersion along the layers. Normal-emission spectra, obtained at different photon energies, indicated vanishing perpendicular dispersion, but in spectra measured under variation of the emission angle some band-edge signatures were seen, which suggests that some perpendicular dispersion remains, in accordance with the LAPW calculations. The lack of dispersion in the normal-emission spectra could be due to intercalation induced structural transformations, leading to stacking disorder. Also correlation effects may contribute. The rigid-band model is found inadequate, except as a crude approximation, for describing the changes during the initial phase of intercalation. It might be used to describe the continued intercalation, however, under condition that the intercalation modified bands are used. The need for studies that probe both electronic and crystallographic structure ͑including defects͒ is stressed. ͓S0163-1829͑98͒08536-1͔

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Section: B Core-level Screeningmentioning

confidence: 96%

Electronic structure of pure and alkali-metal-intercalatedVSe2

et al. 1998

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“…34,35 A pseudo-Voigt function composed of the sum of Gaussian (30%) and Lorentzian (70%) functions was used to fit all peaks and all peak positions were allowed to vary using nonlinear least-squares minimization. 36 For the Au 4f doublet, splitting was fixed at 3.67 eV while for the P 2p doublet a splitting of 0.84 eV was used. 37 All spectra where fitted with the least number of peaks allowing a variation of the FWHM, although the FWHM of a single contributing species was kept constant.…”

Section: Synchrotron Xps Beamline and Sample Preparationmentioning

confidence: 99%

Chemically synthesised atomically precise gold clusters deposited and activated on titania. Part II

Anderson

Adnan

Alvino

et al. 2013

Phys. Chem. Chem. Phys.

113

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Synchrotron XPS was used to investigate a series of chemically synthesised, atomically precise gold clusters Au(n)(PPh3)y (n = 8, 9 and 101, y depending on the cluster size) immobilized on anatase (titania) nanoparticles. Effects of post-deposition treatments were investigated by comparison of untreated samples with analogues that have been heat treated at 200 °C in O2, or in O2 followed by H2 atmosphere. XPS data shows that the phosphine ligands are oxidised upon heat treatment in O2. From the position of the Au 4f(7/2) peak it can be concluded that the clusters partially agglomerate immediately upon deposition. Heating in oxygen, and subsequently in hydrogen, leads to further agglomeration of the gold clusters. It is found that the pre-treatment plays a crucial role in the removal of ligands and agglomeration of the clusters.

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“…This approach seems to work especially well, e.g., in the case of high energy photoelectron and Auger spectra excited from 3d metals. In this particular case, the asymmetry of the core photoelectron lineshapes (due to the sudden creation of electron-hole pairs in the conduction band upon core level photoionization) can be described using an independent model (Hughes and Scarfe, 1996) based on the joint density of electronic states (that can be obtained from density functional calculations) around the atom with the core hole (Novák et al, in preparation). The MC method based on the parameters of the PIA model, combined with an expert system containing extended databases on physical data characterizing photoionization and electron transport in solids, is applicable for simulation of X-ray photoelectron and Auger spectra excited from solid structures (Werner et al, 2014).…”

Section: Modeling/interpreting Electron Spectra Using Classical and Qmentioning

confidence: 99%

Surfaces and Interfaces: Combining Electronic Structure and Electron Transport Models for Describing Electron Spectra

Kövér

2015

Front. Mater.

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Citation:Kövér L (2015) Surfaces and interfaces: combining electronic structure and electron transport models for describing electron spectra. Front. Mater. 2:35. doi: 10.3389/fmats.2015.00035 Surfaces and interfaces: combining electronic structure and electron transport models for describing electron spectra There are many different types of physical and chemical phenomena reflected in electron spectra induced from atoms, molecules, nanostructures, and solids by photons or charged particles. Table 1 compares the spatial, time, and typical excitation energy scales of selected phenomena. The data (Krausz and Ivanov, 2009;Surdutovich and Solov'yov, 2014) in Table 1 demonstrate that the phenomena influencing electron spectra take place on very wide scales, sometimes encompassing differences of many orders of magnitude. This suggests the need for multiscale approaches when extracting electronic structure or chemical analytical information from electron spectra. Electron SpectraElectron spectra induced from solids contain information on (i) the electronic structure (local at atomic, molecular, cluster, and surface/interface level -or delocalized in the bulk of the solid), different single or multiple excitations, and the chemical state resolved chemical composition; (ii) the (ordered, disordered, or amorphous) physical structure of the solid, as well as the lateral or indepth concentration distribution of the constituent chemical species, via effects of electron transport phenomena (including electron diffraction). While core and valence band photoelectron as well as Auger electron spectra reflect the structure of occupied electronic states, shake-up satellites, due to excitations localized at atomic or molecular level, reflect the structure of unoccupied electronic levels. In the case of shake-off excitations, the energy is continuously shared between the two emitted photoelectrons; therefore, the contribution of these phenomena cannot be separated in the photoelectron spectra from the continuous energy distribution background of electrons scattered inelastically in the solid. Shake-off excitations, however, result in energy loss satellite peaks in photoinduced Auger spectra.Core photoelectron peaks carry localized signatures characteristic of the atomic environment of the emitting atom, while valence band photoelectron spectra reflect properties of delocalized electronic states. On the other hand, information on the site projected density of valence electron states can be obtained from the analysis of core-core valence (CCV) or CVV Auger spectra. The shape of the core photoelectron lines can, however, be influenced by delocalized excitations (e.g., by excitation of electron-hole pairs in the conduction bands of metals or by "intrinsic" type plasmon excitations due to the appearance of the core hole).

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Lineshapes in core-level photoemission from metals: I. Theory and computational analysis

Cited by 25 publications

References 19 publications

Electronic structure of pure and alkali-metal-intercalatedVSe2

Electronic structure of pure and alkali-metal-intercalatedVSe2

Chemically synthesised atomically precise gold clusters deposited and activated on titania. Part II

Surfaces and Interfaces: Combining Electronic Structure and Electron Transport Models for Describing Electron Spectra

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