X-Ray Photoelectron Spectroscopic (XPS) Studies of Clean and Ion Beam Bombarded Sb2Te2Se and (Bi0.7Sb0.3)2Se3.0(111) Surfaces

The first detailed study of photoelectron spectra of Sb2Te2Se and (Bi0.7Sb0.3)2Se3 (111) clean and sputtered surfaces is presented as part of an XPS examination of the surface chemistry of these and related materials. The core level binding energies and surface chemical composition have been determined from the XPS data. On substitution of Te by Se in Sb2Te3 leading to Sb2Te2Se the core level binding energies in Sb and Te increase by 0.3 eV while in Bi2Se3 the binding energy of core electrons does not change on replacement of Bi by Sb. The measured core level shifts are caused by changes of the initial state charge distribution and result in increase of average ionicity of bonding in the Sb2Te2Se crystal. The surface composition of Sb2Te2Se sample calculated from intensities of photoelectron spectra agrees well with the bulk composition of the crystal while (Bi0.7Sb0.3)2Se3 sample shows enrichment in Bi. The effect of argon ion bombardment on surface composition for various impact conditions has been investigated. The surface enrichment in Sb and Bi for Sb2Te2Se and (Bi0.7Sb0.3)2Se3 sample due to different atomic sputtering yields is observed. It follows from the relative intensities of photoelectron spectra measured at different detection angles that the ordered arrangement of the superficial layers sampled by the XPS method is damaged by sputtering at ion energies as low as 200 eV and doses I > 2 . 1015 ion/cm2.

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Adsorption and decomposition of ammonia on a W(110) surface: Photoemission fingerprinting and interpretation of the core level binding energies using the equivalent core approximation

Surface Science Letters ◽

10.1016/0167-2584(82)90261-4 ◽

1982 ◽

Vol 119 (2-3) ◽

pp. A295

Author(s):

M. Grunze ◽

C.R. Brundle ◽

D. Tománek

Keyword(s):

Binding Energies ◽

Core Level ◽

The Core ◽

Core Approximation

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Core Level Shifts and Grain Boundary Cohesion

Microscopy and Microanalysis ◽

10.1017/s1431927600023953 ◽

1998 ◽

Vol 4 (S2) ◽

pp. 766-767

Author(s):

D. A. Muller

Keyword(s):

Charge Transfer ◽

Valence Band ◽

Core Level ◽

Level Shift ◽

The Core ◽

Metallic Interfaces ◽

Level Shifts ◽

Electron Energy Loss ◽

Valence Band Width

The role of core level shifts at metallic interfaces has often been ignored in electron energy loss spectroscopy (EELS) even though very small changes in bond length can lead to large core level shifts. However, the popular interpretation of core level shifts as measures of charge transfer is highly problematic. For instance, in binary alloys systems, the core level shifts can be the same sign for both atomic constituents[l]. The simple interpretation would require that both atomic species had lost or gained charge. Further, the signs of the core level shifts can be opposite to those expected from electronegativity arguments[2]. A core level shift (CLS) is still possible, even when no charge transfer occurs. As illustrated in Fig. 1, if the valence band width is increased, the position of the center of the valence band with respect to the Fermi energy will change (as the number of electrons remains unchanged).

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Theoretical core spectroscopy of molecules interacting with ice surfaces

10.5194/egusphere-egu21-1094 ◽

2021 ◽

Author(s):

Richard Asamoah Opoku

Keyword(s):

Electronic Properties ◽

Photoelectron Spectroscopy ◽

Density Functional ◽

Trace Gases ◽

Binding Energies ◽

Photoelectron Spectra ◽

Development Fund ◽

Xps Spectra ◽

The Core ◽

Ice Surfaces

C&#233;line TOUBIN2 and Andr&#233; Severo Pereira GOMES 32,3 Laboratoire de Physique des Lasers, des atomes et des Mol&#233;cules, Universit&#233; de Lille, Cit&#233; Scientifique, 59655 Villeneuve d&#8217;Ascq Cedex, FranceE-mail : [email protected]2 ; [email protected]3Ice plays an essential role as a catalyst for reactions between atmospheric trace gases. The uptake of trace gases to ice has been proposed to have a major impact on geochemical cycles, human health, and ozone depletion in the stratosphere [1]. X-ray photoelectron spectroscopy (XPS) [2], serves as a powerful technique to characterize the elemental composition of such interacting species due to its surface sensitivity. Given the existence of complex physico-chemical processes such as adsorption, desorption, and migration within ice matrix, it is important to establish a theoretical framework to determine the electronic properties of these species under different conditions such as temperature and concentration. The focus of this work is to construct an embedding methodology employing Density Functional (DFT) and Wave Function Theory (WFT) to model and interpret photoelectron spectra of adsorbed halogenated species on ice surfaces at the core level with the highest accuracy possible.&#160;We make use of an embedding approach utilizing full quantum mechanics to divide the system into subunits that will be treated at different levels of theory [3].The goal is to determine core electron binding energies and the associated chemical shifts for the adsorbed halogenated species such as molecular HCl and the dissociated form Cl- at the surface and within the uppermost bulk layer of the ice respectively [4]. The core energy shifts are compared to the data derived from the XPS spectra [4].We show that the use of a fully quantum mechanical embedding method, to treat solute-solvent systems is computationally efficient, yet accurate enough to determine the electronic properties of the solute system (halide ion) as well as the long-range effects of the solvent environment (ice).We acknowledge support by the French government through the Program &#8220;Investissement d'avenir&#8221; through the Labex CaPPA (contract ANR-11-LABX-0005-01) and I-SITE ULNE project OVERSEE (contract ANR-16-IDEX-0004), CPER CLIMIBIO (European Regional Development Fund, Hauts de France council, French Ministry of Higher Education and Research) and French national supercomputing facilities (grants DARI x2016081859 and A0050801859).&#160;

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Core level shifts in Cu–Pd alloys as a function of bulk composition and structure

Surface Science ◽

10.1016/j.susc.2015.02.011 ◽

2015 ◽

Vol 640 ◽

pp. 127-132 ◽

Cited By ~ 9

Author(s):

Jacob R. Boes ◽

Peter Kondratyuk ◽

Chunrong Yin ◽

James B. Miller ◽

Andrew J. Gellman ◽

...

Keyword(s):

Bulk Composition ◽

Core Level ◽

Composition And Structure ◽

Level Shifts

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AB-INITIO CALCULATION OF THE INITIAL- AND FINAL-STATE EFFECTS ON CORE LEVEL SHIFTS AT TRANSITION METAL SURFACES

International Journal of Modern Physics B ◽

10.1142/s0217979293001141 ◽

1993 ◽

Vol 07 (01n03) ◽

pp. 542-545

Author(s):

D. HENNIG ◽

M. METHFESSEL ◽

M. SCHEFFLER

Keyword(s):

Transition Metal ◽

Core Level ◽

Level Shift ◽

Full Potential ◽

Initial State ◽

Final State ◽

State Approximation ◽

Transition Metal Surface ◽

Lmto Method ◽

Level Shifts

The surface core-level shift at a transition metal surface can be calculated in two different ways using the initial-state approximation or using a more involved approach which includes screening of the photo-created core hole. Our calculated results obtained using the full-potential LMTO method for the close packed surfaces of all 4d transition metals within the initial state picture can be well explained by standard arguments.

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