Journal of Electron Spectroscopy and Related Phenomena最新文献

{"title":"Anisotropic dispersion of excitonic bands of the single-crystal pentacene (001) surface as measured by low-energy angle-resolved high-resolution electron energy-loss spectroscopy","authors":"Yasuo Nakayama ,&nbsp;François C. Bocquet ,&nbsp;Ryohei Tsuruta ,&nbsp;Serguei Soubatch ,&nbsp;F. Stefan Tautz","doi":"10.1016/j.elspec.2025.147514","DOIUrl":"10.1016/j.elspec.2025.147514","url":null,"abstract":"<div><div>Low-energy high-resolution electron energy-loss spectroscopy (HREELS) is a useful technique for the characterization of various excitation processes at solid surfaces. However, no successful work has been reported on molecular single-crystal samples yet. In the present study, low-energy angle-resolved HREELS measurements were conducted on single-crystal pentacene, an organic semiconductor. The results confirmed the excitonic bands exhibiting energy–momentum dispersion and anisotropy of these depending on the surface crystallographic directions, corroborating the occurrence of exciton delocalization, contrary to the ordinary notion of the Frenkel exciton for weakly interacting van der Waals molecular solids. The present results demonstrate that low-energy angle-resolved HREELS is applicable to the precise examination of the excitonic characteristics of solid-state surfaces, even for molecular semiconductor single crystals.</div></div>","PeriodicalId":15726,"journal":{"name":"Journal of Electron Spectroscopy and Related Phenomena","volume":"279 ","pages":"Article 147514"},"PeriodicalIF":1.8,"publicationDate":"2025-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143140829","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":"Time evolution of ion states formed during the cascade decay of vacancies produced by the electron capture decay of the 125I radionuclide","authors":"A.P. Chaynikov ,&nbsp;A.G. Kochur ,&nbsp;A.I. Dudenko","doi":"10.1016/j.elspec.2025.147522","DOIUrl":"10.1016/j.elspec.2025.147522","url":null,"abstract":"<div><div>Cascade relaxation of inner-shell vacancies in tellurium atom produced by the electron capture decay of the ¹²⁵I radionuclide is studied using Monte Carlo simulations. Final cascade ions yields and mean final ion charges upon the decay of single-inner-vacancy states Te<em>X</em>^–15<em>p</em>⁵ (<em>X</em> = 1 <em>s</em> to 5 <em>s</em>) were calculated. The time evolution of the cascade ion states is simulated, and the mean final ion charge is found to be stabilized within <em>τ</em>_casc = 10^–12 s after the electron capture decay of the ¹²⁵I nucleus. This time interval must be compared to the time <em>τ</em>_neutr needed for ions neutralization when ¹²⁵I is used as an Auger emitter in radiotherapy. Depending on the relation between <em>τ</em>_casc and <em>τ</em>_neutr, either ‘isolated-atom’ or ‘condensed-phase’ approximation should be used in theoretical descriptions of local energy deposition.</div></div>","PeriodicalId":15726,"journal":{"name":"Journal of Electron Spectroscopy and Related Phenomena","volume":"279 ","pages":"Article 147522"},"PeriodicalIF":1.8,"publicationDate":"2025-01-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143140828","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":"Density functional theory calculations of the electronic structure and dielectric properties of metal oxide systems Al2O3, MgO, Cu2O, TiO2, WO3","authors":"Raul E. Gutierrez ,&nbsp;Ivana Matanovic ,&nbsp;Maciej P. Polak ,&nbsp;Dane Morgan ,&nbsp;Edl Schamiloglu","doi":"10.1016/j.elspec.2024.147512","DOIUrl":"10.1016/j.elspec.2024.147512","url":null,"abstract":"<div><div>Density Functional Theory is utilized to study the electronic structure and dielectric properties of various metal oxide systems (Al₂O₃, MgO, Cu₂O, TiO₂, WO₃) in comparison to their base metals (Al, Mg, Cu, Ti, and W). The properties studied include the density of states, energy band gap, Fermi energy, work function, ionization potential, and the frequency- and momentum-dependent energy loss function. This work provides high-quality first principles-calculated properties that can be further utilized in computational simulations which aim to model complicated electron inelastic scattering interactions in metal oxides and their corresponding metals. In general, properties of this nature might be of interest, but not limited, to those involved in the multipactor effect, magnetic confinement fusion, photovoltaics, charged particle accelerators, x-ray photoelectron spectroscopy, Auger electron spectroscopy, and photomultipliers.</div></div>","PeriodicalId":15726,"journal":{"name":"Journal of Electron Spectroscopy and Related Phenomena","volume":"278 ","pages":"Article 147512"},"PeriodicalIF":1.8,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143180515","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":"XPS study on the oxidation-induced segregation behavior of U–Nb alloy","authors":"Ruidong Liu,&nbsp;Xiaofang Wang,&nbsp;Lizhuo Luo,&nbsp;Yin Hu,&nbsp;Jianwei Qin,&nbsp;Yongchu Rao","doi":"10.1016/j.elspec.2024.147513","DOIUrl":"10.1016/j.elspec.2024.147513","url":null,"abstract":"<div><div>In this work, the surface structure and chemical composition of U–Nb alloy after one year of oxidation under ambient conditions were investigated using X-ray photoelectron spectroscopy (XPS) depth profile methods. Furthermore, the in-situ oxidation of U–Nb was carried out under UHV conditions, providing insights into the initial oxidation behavior of U-Nb. Studies show that, an thin (1.5 nm) layer of UO₂ intermixed with enriched Nb₂O₅ is formed on the top of the naturally oxidized U–Nb, with an inner oxide layer consisting of UO_2-x intermixed with depleted NbO₂ and NbO at below, followed by an inner layer of UO_2-x intermixed with metallic U and Nb adjacent to the U-Nb substrate. During the initial oxidation stage, U oxidizes rapidly to form UO_2-x, while the leaving Nb in the UO_2-x lattice migrates inward and enriched at the metal side of the oxide/metal interface. As oxidation continues, oxidation-induced segregation of the leaving Nb in the UO_2-x lattice toward the surface occurs and forms NbO and NbO₂ at the gas-oxide interface. The affinities of U and Nb to OH and O anions may act as the driving force of the segregation.</div></div>","PeriodicalId":15726,"journal":{"name":"Journal of Electron Spectroscopy and Related Phenomena","volume":"278 ","pages":"Article 147513"},"PeriodicalIF":1.8,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143104952","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":"Embedding of cluster models of oxides: Implications for XPS predictions","authors":"Paul S. Bagus ,&nbsp;Connie J. Nelin","doi":"10.1016/j.elspec.2024.147511","DOIUrl":"10.1016/j.elspec.2024.147511","url":null,"abstract":"<div><div>The importance of embedding cluster models of NiO that are used to predict and analyze the Ni 2p XPS spectra in this compound is studied. The XPS obtained with an isolated NiO₆ cluster are compared with those obtained with the cluster embedded in a point charge field designed to reproduce the Madelung potential of the crystal. It is found that there is a remarkable and possibly unexpected similarity between the theoretical XPS spectra with and without point charge embedding. It is believed that this can be expected to be a general conclusion relevant for the XPS of other ionic compounds.</div></div>","PeriodicalId":15726,"journal":{"name":"Journal of Electron Spectroscopy and Related Phenomena","volume":"278 ","pages":"Article 147511"},"PeriodicalIF":1.8,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143180514","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":"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}