Journal of Electron Spectroscopy and Related Phenomena最新文献

{"title":"Theory of circular dichroism in angle- and spin-resolved photoemission from the surface state on Bi(111)","authors":"E.E. Krasovskii","doi":"10.1016/j.elspec.2024.147501","DOIUrl":"10.1016/j.elspec.2024.147501","url":null,"abstract":"<div><div>Circular dichroism (CD) of photoemission from a surface state on Bi(111) is considered within an <em>ab initio</em> one-step theory of photoemission. The symmetry of the azimuthal distribution of CD for different spin directions is discussed in terms of the spin structure of the initial states. Both normal and off-normal light incidence are considered. Strong photon energy dependence of photoemission in the ultraviolet range is observed. The principal difference between the initial state spin polarization and the spin photocurrent is emphasized and problems with revealing the orbital angular moment with photoemission are pointed to.</div></div>","PeriodicalId":15726,"journal":{"name":"Journal of Electron Spectroscopy and Related Phenomena","volume":"277 ","pages":"Article 147501"},"PeriodicalIF":1.8,"publicationDate":"2024-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142706887","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Elucidating the structure of amorphous-carbon films containing carbide and non-carbide-forming metals","authors":"J.L. Endrino","doi":"10.1016/j.elspec.2024.147500","DOIUrl":"10.1016/j.elspec.2024.147500","url":null,"abstract":"<div><div>This work makes a first comparison of the structural features of the amorphous carbon matrix in <em>a-</em>C:Mo and <em>a-</em>C:Au films deposited using the pulsed filter cathodic arc technique. The present study combines synchrotron X-ray absorption (XAS) and emission (XES) in conjunction with transmission electron microscopy observations and selective area diffraction (SADP). While diffraction techniques can be used to indicate the formation of crystalline particles for the metal phase, and transmission electron microscope (TEM) images can be used to indicate the clustering and formation of metallic nanoparticles, the collection of X-ray absorption (XAS) and X-ray emission (XES) spectra is a valuable approach to elucidate the electronic structure of the surrounding amorphous carbon phase and interpret their physical properties.</div></div>","PeriodicalId":15726,"journal":{"name":"Journal of Electron Spectroscopy and Related Phenomena","volume":"277 ","pages":"Article 147500"},"PeriodicalIF":1.8,"publicationDate":"2024-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142661488","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Atomic data, and ionization cross-sections by electron impact of tungsten ions, W LXV","authors":"A.A. El-Maaref ,&nbsp;A.E. Elmeshneb ,&nbsp;W. Osman","doi":"10.1016/j.elspec.2024.147499","DOIUrl":"10.1016/j.elspec.2024.147499","url":null,"abstract":"<div><div>In the current study, we present a comprehensive investigation of Ne-like tungsten, W LXV. Spectroscopic properties, energies, and transition rates of the configuration list containing 2 s²2p⁶, 2 s²2p⁵3<em>l</em>, 2 s²2p⁴3<em>l</em>², 2s2p⁶3<em>l</em>, and 2s2p⁵3<em>l</em>3<em>l´, l</em> = s, p, and d, and <em>l´</em> = <em>p</em> and <em>d</em>, have been computed using the multi-configuration Dirac-Hartree-Fock method (MCDHF) and FAC code. Single and double electron excitations are performed to calculate the atomic data precisely. Also, the correlations from the upper atomic states with the principal quantum number, <span><math><mrow><mi>n</mi><mo>=</mo><mspace></mspace><mn>4</mn><mo>,</mo><mspace></mspace><mn>5</mn><mo>,</mo></mrow></math></span> and <span><math><mn>6</mn></math></span>, are involved in the present calculations. All contributions from the orbitals <span><math><mrow><mi>s</mi><mo>,</mo><mi>p</mi><mo>,</mo><mi>d</mi><mo>,</mo><mi>f</mi><mo>,</mo></mrow></math></span> and <span><math><mi>g</mi></math></span> have also been correlated to configuration interaction (CI) calculations. In addition to CI and upper-level correlations, the quantum-electrodynamics effects have been considered as well. Moreover, the FAC code has been utilized to evaluate the ionization cross-section by electron impact of the present ion. The electron impact (EI) cross-sections of the ionizing states 2 s²2p⁶ (₁S₀) and 2 s²2p⁵3 s (¹P₁, ³P_0,1,2) to 2 s²2p⁵ (²P_3/2) have been computed, as well as the total cross-sections of previously mentioned states in W LXV for a wide range of collision energies (up to 150 keV). Furthermore, the effect of increasing the principal quantum number (n) and the inclusion of a complete set of configurations on the cross-section values is examined.</div></div>","PeriodicalId":15726,"journal":{"name":"Journal of Electron Spectroscopy and Related Phenomena","volume":"277 ","pages":"Article 147499"},"PeriodicalIF":1.8,"publicationDate":"2024-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142661487","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Encoder–decoder neural networks in interpretation of X-ray spectra","authors":"Jalmari Passilahti,&nbsp;Anton Vladyka,&nbsp;Johannes Niskanen","doi":"10.1016/j.elspec.2024.147498","DOIUrl":"10.1016/j.elspec.2024.147498","url":null,"abstract":"<div><div>Encoder–decoder neural networks (EDNN) condense information most relevant to the output of the feedforward network to activation values at a bottleneck layer. We study the use of this architecture in emulation and interpretation of simulated X-ray spectroscopic data with the aim to identify key structural characteristics for the spectra, previously studied using emulator-based component analysis (ECA). We find an EDNN to outperform ECA in covered target variable variance, but also discover complications in interpreting the latent variables in physical terms. As a compromise of the benefits of these two approaches, we develop a network where the linear projection of ECA is used, thus maintaining the beneficial characteristics of vector expansion from the latent variables for their interpretation. These results underline the necessity of information recovery after its condensation and identification of decisive structural degrees of freedom for the output spectra for a justified interpretation.</div></div>","PeriodicalId":15726,"journal":{"name":"Journal of Electron Spectroscopy and Related Phenomena","volume":"277 ","pages":"Article 147498"},"PeriodicalIF":1.8,"publicationDate":"2024-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142706886","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comparison of soft X-ray spectro-ptychography and scanning transmission X-ray microscopy","authors":"Adam P. Hitchcock ,&nbsp;Chunyang Zhang ,&nbsp;Haytham Eraky ,&nbsp;Drew Higgins ,&nbsp;Rachid Belkhou ,&nbsp;Nicolas Millle ,&nbsp;Sufal Swaraj ,&nbsp;Stefan Stanescu ,&nbsp;Tianxiao Sun ,&nbsp;Jian Wang","doi":"10.1016/j.elspec.2024.147487","DOIUrl":"10.1016/j.elspec.2024.147487","url":null,"abstract":"<div><div>Over the past decade advances in instrumentation and software have enabled development of spectro-ptychography (SP) as a higher spatial resolution extension of scanning transmission X-ray microscopy (STXM). Direct comparisons are made of same-area chemical state imaging of Cu nanoparticles using STXM and SP in order to compare and contrast the two approaches. We show that SP gives very similar chemical state information as STXM with significantly better spatial resolution and much higher quality images and chemical maps, on account of finer pixels in the reconstructed images. When defocused spot sizes are used (i.e., 1–3 μm, as opposed to full-focus 30–50 nm) SP data acquisition is faster and the radiation dose delivered to the sample is smaller than the corresponding STXM measurement. The limitations of SP are primarily related to the time and complexity of the ptychographic reconstruction. We argue that these documented advantages mean that SP rather than STXM should be used for more complex studies such as tomography and <em>in situ</em> studies, especially when radiation damage is a concern. The main point of this manuscript is to illustrate, with scientifically relevant samples, the significant advantages of SP relative to conventional STXM, with the goal of encouraging greater use of SP.</div></div>","PeriodicalId":15726,"journal":{"name":"Journal of Electron Spectroscopy and Related Phenomena","volume":"276 ","pages":"Article 147487"},"PeriodicalIF":1.8,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142427619","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Polarization measurement of vacuum ultraviolet light using visible fluorescence from neon atoms","authors":"Tatsuo Kaneyasu ,&nbsp;Harunobu Takeda ,&nbsp;Kouichi Hosaka ,&nbsp;Jun-ichi Adachi","doi":"10.1016/j.elspec.2024.147488","DOIUrl":"10.1016/j.elspec.2024.147488","url":null,"abstract":"<div><div>The polarization state of the vacuum ultraviolet light has been studied with a fluorescence polarimeter based on the conversion of short wavelength light into visible fluorescence via atomic resonance. In addition to the previously established method using helium atoms, the results show that polarization state of vacuum ultraviolet light can be evaluated by observing the visible fluorescence emitted from neon atoms. This study demonstrates that a fluorescence polarimeter can be used in conjunction with a variety of atoms and molecules and thus extends the range of wavelengths to which this method can be applied.</div></div>","PeriodicalId":15726,"journal":{"name":"Journal of Electron Spectroscopy and Related Phenomena","volume":"276 ","pages":"Article 147488"},"PeriodicalIF":1.8,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142427520","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A reassessment of 5f occupation in plutonium","authors":"JG Tobin","doi":"10.1016/j.elspec.2024.147478","DOIUrl":"10.1016/j.elspec.2024.147478","url":null,"abstract":"<div><p>A detailed spectroscopic simulation of the original Pu N_4,5 and O_4,5 X-Ray Absorption Spectroscopy (XAS) has been performed. Additionally, a fundamental flaw in the Electron Energy Loss Spectroscopy (EELS) measurement has been corrected. Thus, the determination of the 5f occupation (n) in elemental Pu has been re-evaluated with the result that n = 5.0 ± 0.1 for αPu and n = 4.9 ± 0.2 for δPu. These values are significantly lower than the value of ∼5½ that was propagated earlier.</p></div>","PeriodicalId":15726,"journal":{"name":"Journal of Electron Spectroscopy and Related Phenomena","volume":"276 ","pages":"Article 147478"},"PeriodicalIF":1.8,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142240679","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Intensity-energy response function of Al/Cr-Kα x-ray photoemission instruments: An inter-laboratory study","authors":"David Alamarguy ,&nbsp;Damien Aureau ,&nbsp;Thierry Conard ,&nbsp;Nicolas Gauthier ,&nbsp;Frédéric Georgi ,&nbsp;Stéphane Guilet ,&nbsp;Samar Hajjar-Garreau ,&nbsp;Olivier Heintz ,&nbsp;Guillaume Monier ,&nbsp;Christophe Méthivier ,&nbsp;Hervé Montigaud ,&nbsp;Samantha Soulé ,&nbsp;Olivier Renault ,&nbsp;Rémi Lazzari","doi":"10.1016/j.elspec.2024.147486","DOIUrl":"10.1016/j.elspec.2024.147486","url":null,"abstract":"<div><p>The question of the intensity-energy response of photoemission spectrometers has been approached through a round-robin involving 13 instruments working with low (Al/Mg-K<span><math><mi>α</mi></math></span>) and high (Cr-K<span><math><mi>α</mi></math></span>) energy photon sources. An algorithm based on the analysis of inelastic background previously proposed [S. Guilet et al., J. Electron Spectrosc. Relat. Phenom. 285 (2022) 147225)] was intensively tested against calibrated Al/Mg-K<span><math><mi>α</mi></math></span> instruments and calculated relative sensitivity factors (RSFs) over the 15 core level peaks of coinage metals (Ag, Au, Cu). In both cases, the linear correlation within <span><math><mrow><mo>±</mo><mn>10</mn></mrow></math></span> %, over two orders of magnitude in intensity and for kinetic energies ranging from <span><math><mrow><mo>∼</mo><mn>400</mn></mrow></math></span> to <span><math><mrow><mspace></mspace><mn>1400</mn><mspace></mspace><mi>eV</mi></mrow></math></span>, showed the consistency of the approach. All the contributions to RSFs (<em>e.g.</em> non-dipolar terms in the photo-ionization cross section, elastic scattering effects, surface excitations, beam polarization by the monochromator) were critically reviewed and taken into account using the state-of-the-art modellings and databases. Strong variations were evidenced among instruments, regarding not only the response functions, but also the theoretical RSFs due to different measurement geometries. For the Cr-K<span><math><mi>α</mi></math></span> hard x-ray instruments, the same analysis was performed with a set of different materials (Al, Si, Ge, Fe, Co, Ni, Cu, Zn, Nb, Mo, Ag, W, Au). A <span><math><mrow><mo>±</mo><mn>10</mn></mrow></math></span> % satisfactory agreement against theoretical RSFs over 69 core levels spanning a large kinetic energy range (300–4000 eV) could be achieved with a common response function. Despite limitations that are reviewed, this work opens interesting perspectives for a systematic calibration of photoemission instruments.</p></div>","PeriodicalId":15726,"journal":{"name":"Journal of Electron Spectroscopy and Related Phenomena","volume":"276 ","pages":"Article 147486"},"PeriodicalIF":1.8,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142241171","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A semiempirical model for low energy electron–atom transport cross sections: The case of noble gases","authors":"Felipe Arretche ,&nbsp;Eliton P. Seidel ,&nbsp;Wagner Tenfen","doi":"10.1016/j.elspec.2024.147476","DOIUrl":"10.1016/j.elspec.2024.147476","url":null,"abstract":"<div><p>A semiempirical approach to describe low energy electron–atom transport cross sections of easy implementation and reproduction is presented. The heart of the model is an energy independent two-parameter potential that was adjusted to reproduce the accurate total cross sections for He, Ne, Ar and Kr, measured with a threshold photoelectron source technique from meV up to 20 eV. Once the potential was conceived, the model was validated by comparing the values obtained for the calculated scattering lengths and phase shifts with the respective quantities previously reported in the literature. We close the article by presenting the momentum transfer and viscosity cross sections. Good agreement is found when compared to the similar data obtained from swarm experiments, from phase shifts according to differential cross section measurements and to the cross sections reported by sophisticated <em>ab initio</em> relativistic many-body calculations. Tables for the phase shifts and cross sections are provided for direct use and applications.</p></div>","PeriodicalId":15726,"journal":{"name":"Journal of Electron Spectroscopy and Related Phenomena","volume":"275 ","pages":"Article 147476"},"PeriodicalIF":1.8,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142098470","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Synchrotron scanning transmission x-ray spectro-microscopy (STXM) characterisation of β-SiC nanowhisker AZ91 magnesium alloy nanocomposites","authors":"Zhuocheng Xu ,&nbsp;Xinyi Hao ,&nbsp;Yuting Dai ,&nbsp;Christian Kübel ,&nbsp;Milo S.P. Shaffer ,&nbsp;Benjamin Watts ,&nbsp;Qianqian Li","doi":"10.1016/j.elspec.2024.147477","DOIUrl":"10.1016/j.elspec.2024.147477","url":null,"abstract":"<div><p>β-SiC nanoparticles are one of the most common reinforcements in Mg-Al alloy matrix nanocomposites (MgMNCs). The interfacial interactions between β-SiC and the alloy matrix are complex due to the occurrence of new phases and the fine scale of the 3D architecture. This study aims to explore the feasibility of using synchrotron Scanning Transmission X-ray spectro-Microscopy (STXM) to investigate such interfacial interactions and acquire reference X-ray Absorption Spectroscopy (XAS) data for some common interphase crystals present within the composites, which are not readily available. Throughout this study, a reliable procedure for collecting STXM data on samples derived from MgMNCs was developed, and reference XAS spectra for α-Mg, β-Mg₁₇Al₁₂, T2-Al₂MgC₂, Mg₂Si and MgO present in MgMNCs were collected. The accessibility of STXM and spatially resolved XAS spectrum is not only useful for nanocomposite alloy research but applicable widely across the magnesium alloy research community when identifying and quantifying the phases with complex crystal structures and oxide states.</p></div>","PeriodicalId":15726,"journal":{"name":"Journal of Electron Spectroscopy and Related Phenomena","volume":"276 ","pages":"Article 147477"},"PeriodicalIF":1.8,"publicationDate":"2024-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0368204824000604/pdfft?md5=cf5a99b62862d53eb59335e8679447e9&pid=1-s2.0-S0368204824000604-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142151392","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}