Journal of Electron Spectroscopy and Related Phenomena最新文献

英文中文

Electron inelastic mean free path in MoO3 thin films MoO3薄膜中的电子非弹性平均自由程

IF 1.5 4区物理与天体物理 Q2 SPECTROSCOPY

Journal of Electron Spectroscopy and Related Phenomena

Pub Date : 2026-02-09 DOI: 10.1016/j.elspec.2026.147602

Georghii Tchoudinov , Seyed Javad Rezvani , Stefano Nannarone , Andrea Di Cicco

Determination of the electron inelastic mean free path (IMFP) in complex and functional materials is a fascinating problem for which scattered results can be found in present literature. Knowledge of the IMFP is crucial in determining the probing depth of several important techniques based on the collection of electrons excited by external probes. In particular no experimental data can be found for several oxides including MoO

_{3}

, a promising material used in several forms for applications. To the purpose of measuring the IMFP, we performed accurate constant initial state (CIS) Si2p photoemission experiments on Si wafers covered with layers of amorphous MoO

_{3}

of variable thickness, using synchrotron radiation in a variable photon energy range 135–280 eV at the BEAR beamline at Elettra. In particular the SiO

_{x}

photoemission peak has been analyzed, selecting only those photoelectrons which originate from the native oxide layer of the silicon wafer. The electron Inelastic Mean Free Path has been derived using a first-order treatment for elastic scattering. This latter is justified by the particular experimental conditions, namely the use of a thin overlayer and a small analyzer acceptance angle. Present IMFP results are compared with previous semi-empirical models, improving our present knowledge of the IMFP curve in amorphous MoO

_{3}

and opening new experimental possibilities for accurate measurements of the probing depth in functional materials.

复杂功能材料中电子非弹性平均自由程（IMFP）的测定是一个令人着迷的问题，在目前的文献中可以找到分散的结果。在确定基于外部探针激发的电子收集的几种重要技术的探测深度时，IMFP的知识是至关重要的。特别是没有找到包括MoO3在内的几种氧化物的实验数据，MoO3是一种以多种形式用于应用的有前途的材料。为了测量IMFP，我们利用同步辐射在Elettra的BEAR光束线上进行了精确的恒定初始态（CIS） Si2p光电发射实验，该实验在覆盖有变厚度的非晶MoO3层的硅晶片上进行，其光子能量范围为135-280 eV。特别地，我们分析了SiOx的光发射峰，只选择了那些来自硅片的天然氧化层的光电子。利用弹性散射的一阶处理，导出了电子的非弹性平均自由程。后者在特殊的实验条件下是合理的，即使用薄的覆盖层和小的分析仪接受角。本文的IMFP结果与以往的半经验模型进行了比较，提高了我们目前对非晶MoO3的IMFP曲线的认识，并为准确测量功能材料的探测深度开辟了新的实验可能性。

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引用次数: 0

Franck–Condon profiles for the X2B1 ← X1A1 band of the anion photoelectron spectroscopy of OIO based on discrete variable representation 基于离散变量表示的OIO阴离子光电子能谱X2B1←X1A1波段的frank - condon谱线

IF 1.5 4区物理与天体物理 Q2 SPECTROSCOPY

Journal of Electron Spectroscopy and Related Phenomena

Pub Date : 2026-01-30 DOI: 10.1016/j.elspec.2026.147593

Guohua Xu

The three-dimensional potential energy surfaces around the equilibrium geometries of OIO‾(X¹A₁) and OIO(X²B₁) were calculated with two double hybrid density functionals XYGJ-OS and XDH-PBE0 and three hybrid density functionals B3LYP, MPW1PBE and B97–3 in conjunction with various basis sets. The potential energy surfaces were used in calculations of anharmonic vibrational wavefunctions of OIO‾(X¹A₁) and OIO(X²B₁) by virtue of discrete variable representation. Therefrom, the vibrational frequencies including anharmonicity of both states were obtained, and the Franck-Condon factors between these two states were calculated including allowance for anharmonicity and Duschinsky effect. The X²B₁ ← X¹A₁ band of the anion photoelectron spectroscopy of OIO was then simulated using the computed Franck-Condon factors broadened with a Gaussian line shape. Based on the theoretical Franck-Condon factors, a more detailed assignment of the observed vibrational structure of the photoelectron spectrum, which includes the photodetachment from vibrational excited states of OIO‾(X¹A₁) has been proposed. Comparison between the simulated and experimental spectra by iterative Franck-Condon analysis procedure has been made, the equilibrium geometrical parameters for OIO anion have been derived to be r(OI)= 1.8508 ± 0.0003 Å and θ(OIO)= 107.9 ± 0.3º.

利用XYGJ-OS和XDH-PBE0两个双杂化密度泛函以及B3LYP、MPW1PBE和B97-3三个杂化密度泛函结合各种基集，计算了OIO（X1A1）和OIO（X2B1）平衡几何形状周围的三维势能面。利用离散变量表面法，将势能面用于计算OIO的无谐振动波函数，其形式为OIO的X1A1和X2B1。由此得到了两种状态包含非谐性的振动频率，并计算了两种状态之间包含非谐性和Duschinsky效应的frank - condon因子。然后用计算得到的frank - condon因子对OIO阴离子光电子能谱的X2B1←X1A1波段进行了高斯线形展宽模拟。基于理论的frank - condon因子，对观察到的光电子能谱的振动结构进行了更详细的分配，其中包括OIO （X1A1）的振动激发态的光脱离。将模拟光谱与实验光谱进行了对比，得到了OIO阴离子的平衡几何参数为r(OI)= 1.8508 ± 0.0003 Å， θ(OIO)= 107.9 ± 0.3º。

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引用次数: 0

Automated determination of ionization energy and electron affinity from UPS and LEIPS spectra based on piecewise polynomial fitting 基于分段多项式拟合的UPS和LEIPS光谱电离能和电子亲和力的自动测定

IF 1.5 4区物理与天体物理 Q2 SPECTROSCOPY

Journal of Electron Spectroscopy and Related Phenomena

Pub Date : 2026-01-01 DOI: 10.1016/j.elspec.2025.147591

Daichi Egami , Hiroyuki Yoshida

Precise determination of ionization energy (IE) and electron affinity (EA) is essential for elucidating the electronic structure of semiconductors. In the solid state, these quantities are most accurately obtained from the spectral onsets of ultraviolet photoelectron spectroscopy (UPS) and low-energy inverse photoelectron spectroscopy (LEIPS), respectively. Conventional onset determination relies on manual fitting, which is time-consuming and requires experience. For future automated measurements, automated data analysis will be indispensable. Here, we propose an automated analysis approach that combines piecewise polynomial fitting with tangent intersection to extract IE and EA from UPS and LEIPS spectra. Applied to various organic semiconductors and polymer samples, the automated results exhibit excellent agreement with manual analysis, achieving accuracies of ±0.002 eV for UPS and ±0.02 eV for LEIPS—well below the commonly assumed uncertainties and instrumental resolutions of these techniques. The method demonstrates robust performance even for spectra with low signal-to-noise ratios or unclear onset, with no outliers exceeding 0.1 eV. This framework offers a reliable solution for automated spectral analysis, paving the way for large-scale database development and data-driven materials discovery.

电离能（IE）和电子亲和能（EA）的精确测定对于阐明半导体的电子结构至关重要。在固体状态下，这些量分别从紫外光电子能谱（UPS）和低能逆光电子能谱（LEIPS）的光谱起点得到。传统的起病时间测定依赖于人工拟合，耗时且需要经验。对于未来的自动化测量，自动化数据分析将是不可或缺的。本文提出了一种将分段多项式拟合与切线相交相结合的自动分析方法，从UPS和LEIPS光谱中提取IE和EA。应用于各种有机半导体和聚合物样品，自动化结果与人工分析非常吻合，UPS的精度为±0.002 eV， leips的精度为±0.02 eV，远低于这些技术通常假设的不确定度和仪器分辨率。即使对于低信噪比或起始不明确的光谱，该方法也表现出鲁棒性，没有超过0.1 eV的异常值。该框架为自动化光谱分析提供了可靠的解决方案，为大规模数据库开发和数据驱动的材料发现铺平了道路。

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引用次数: 0

Automated analysis of low-energy inverse photoelectron spectra using machine learning 利用机器学习的低能逆光电子能谱自动分析

IF 1.5 4区物理与天体物理 Q2 SPECTROSCOPY

Journal of Electron Spectroscopy and Related Phenomena

Pub Date : 2026-01-01 DOI: 10.1016/j.elspec.2025.147589

Yuki Kusano , Hiroyuki Yoshida

The electron affinity (EA) of semiconductors is the energy of the conduction band edge with respect to the vacuum level and represents the electron conduction level. The EAs of organic semiconductors are most precisely determined by low-energy inverse photoelectron spectroscopy (LEIPS). However, data analysis to determine EA from a LEIPS spectrum requires skilled analysts and time-consuming procedures. In this study, we developed a machine learning-based automated analysis method. The vacuum level was determined with an accuracy of 0.01 eV by analyzing the low-energy electron transmission (LEET) spectrum using linear regression. The onset of the LEIPS spectrum was determined by applying Random Forest and Gradient Boosting as learning models to 253 experimental LEIPS spectra derived from measurements of 27 organic semiconductors as the training dataset. By implementing the smoothing process and augmenting the training data in the energy direction, we achieved a prediction accuracy of within ±0.2 eV (±0.1 eV) for 90 % (70 %) and 91 % (74 %) of the test data as the average of six partitions for the Gradient Boosting and Random Forest models, respectively. The fully automated determination of EA is realized by the combined use of LEET and LEIPS spectral onset analyses.

半导体的电子亲和力（EA）是导电带边缘相对于真空水平的能量，代表了电子的导电水平。低能逆光电子能谱（LEIPS）是测定有机半导体电子能谱最精确的方法。然而，从LEIPS谱中确定EA的数据分析需要熟练的分析人员和耗时的过程。在这项研究中，我们开发了一种基于机器学习的自动分析方法。利用线性回归分析低能电子透射（LEET）光谱，确定真空度，精度为0.01 eV。采用随机森林（Random Forest）和梯度增强（Gradient Boosting）作为学习模型，以27种有机半导体测量得到的253个LEIPS光谱作为训练数据集，确定了LEIPS光谱的起始点。通过实现平滑处理并在能量方向上增强训练数据，我们对梯度增强和随机森林模型的6个分区的平均值，分别对90 %（70 %）和91 %（74 %）的测试数据实现了±0.2 eV（±0.1 eV）以内的预测精度。结合LEET和LEIPS光谱起始分析，实现了EA的全自动测定。

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引用次数: 0

Ionization study of C2N2, C4N2, and C6N2 molecules relevant to astrophysical environment 与天体物理环境相关的C2N2、C4N2和C6N2分子的电离研究

IF 1.5 4区物理与天体物理 Q2 SPECTROSCOPY

Journal of Electron Spectroscopy and Related Phenomena

Pub Date : 2026-01-01 DOI: 10.1016/j.elspec.2025.147590

Bini Thomas, Dhanoj Gupta

We report the theoretical investigations of electron impact ionization processes on astrophysically important molecules

C_{2} N_{2}

C_{4} N_{2}

, and

C_{6} N_{2}

, which are relevant to Titan’s atmosphere. We report partial, direct, and total ionization cross section and the corresponding ionization rate coefficients for these targets. The calculations were carried out using the binary encounter Bethe (BEB) model, modified BEB and the mass spectrum dependence (MSD) methods applied over a broad energy range from ionization thresholds up to 5000 eV. The total ionization cross section results show good agreement with previously reported values in the literature. This study provides a theoretically new and detailed analysis of the dissociative ionization processes by electron impact and reports for the first time the ionization rate coefficients for these molecules. The direct ionization cross section for positron impact is also calculated for which there are no data. Furthermore, we have theoretically determined the appearance energies of the cations originating from the parent molecule.

本文报道了与土卫六大气有关的天体物理重要分子C2N2、C4N2和C6N2的电子碰撞电离过程的理论研究。我们报告了这些目标的部分、直接和总电离截面以及相应的电离速率系数。计算采用双相遇Bethe （BEB）模型、修正BEB模型和质谱依赖（MSD）方法，应用于从电离阈值到5000 eV的广泛能量范围内。总电离截面结果与文献中先前报道的值一致。本研究为电子冲击离解电离过程提供了新的理论和详细的分析，并首次报道了这些分子的电离速率系数。在没有数据的情况下，还计算了正电子撞击的直接电离截面。此外，我们从理论上确定了来自母体分子的阳离子的外观能。

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引用次数: 0

Improved magnetic domain imaging in photoelectron emission microscopy using symmetry analysis and momentum selection 利用对称分析和动量选择改进光电子发射显微镜磁畴成像

IF 1.5 4区物理与天体物理 Q2 SPECTROSCOPY

Journal of Electron Spectroscopy and Related Phenomena

Pub Date : 2026-01-01 DOI: 10.1016/j.elspec.2026.147592

Frank O. Schumann , Jürgen Henk

Magnetic circular dichroism in photoemission provides a powerful tool for probing the electronic and magnetic structure of ferromagnets. In the threshold regime, the use of laboratory light sources enables magnetic domain imaging with photoelectron emission microscopy (PEEM), but the achievable magnetic contrast is typically weak, leading to long acquisition times. In this work, we present a theoretical study of contrast enhancement in threshold-photoemission PEEM based on symmetry considerations and relativistic one-step photoemission calculations. We show that surface symmetry imposes specific relations among the fundamental dichroic intensities and the corresponding asymmetries, which can be exploited by momentum selection using an aperture in the PEEM. As a prototype system, we investigate in-plane and perpendicular magnetized Fe(001). Our results demonstrate that sizable magnetic domain contrast can be achieved at low photon energies by selecting appropriate emission directions, providing a practical route toward efficient laboratory-based magnetic domain imaging.

光发射中的磁圆二色性为研究铁磁体的电子和磁性结构提供了有力的工具。在阈值范围内，使用实验室光源可以使用光电子发射显微镜（PEEM）进行磁畴成像，但可实现的磁对比度通常较弱，导致采集时间长。在这项工作中，我们提出了基于对称性考虑和相对论一步光发射计算的阈值光发射PEEM对比度增强的理论研究。我们表明，表面对称性在基本二色性强度和相应的不对称性之间施加了特定的关系，这种关系可以通过使用PEEM中的孔径进行动量选择来利用。作为原型系统，我们研究了平面内和垂直磁化铁（001）。我们的研究结果表明，通过选择合适的发射方向，可以在低光子能量下获得相当大的磁畴对比度，为高效的实验室磁畴成像提供了一条实用的途径。

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引用次数: 0

XPS diagnostics of GaAs-based semiconductors with surface cleaning by ion etching 离子蚀刻表面清洗gaas基半导体的XPS诊断

IF 1.5 4区物理与天体物理 Q2 SPECTROSCOPY

Journal of Electron Spectroscopy and Related Phenomena

Pub Date : 2025-12-12 DOI: 10.1016/j.elspec.2025.147587

V.M. Mikoushkin, E.A. Markova

Ar⁺ etching the surface of GaAs-based semiconductors, required in XPS, drastically changes the core-level binding energies (BEs) in n-GaAs, SI-GaAs and p-GaAs, so that the BE shift can exceed the chemical one. The ion etching forms a p-GaAs surface layer with BEs ∼1.2 eV higher than in n-GaAs. To obtain information about the bulk unirradiated layer, the energy of bombarding ions should be reduced, whereas photon energy and the XPS energy resolution should be increased.

XPS中需要的Ar+蚀刻gaas基半导体表面，会极大地改变n-GaAs、SI-GaAs和p-GaAs的核心能级结合能（BEs），从而使BE位移超过化学位移。离子蚀刻形成的p-GaAs表面层BEs ~ 1.2 eV高于n-GaAs。为了获得体未辐照层的信息，应该降低轰击离子的能量，而提高光子能量和XPS能量分辨率。

引用次数: 0

L- shell X-ray production cross sections for Au and Bi induced by 30 MeV to 75 MeV boron ions 30 MeV至75 MeV硼离子诱导Au和Bi的L壳层x射线生成截面

IF 1.5 4区物理与天体物理 Q2 SPECTROSCOPY

Journal of Electron Spectroscopy and Related Phenomena

Pub Date : 2025-12-11 DOI: 10.1016/j.elspec.2025.147588

Balwinder Singh , Shehla , Anil Kumar , Deepak Swami , Ajay Kumar , Sanjiv Puri

In the present work, the experimental cross sections for production of the L X-rays in Au and Bi by impact of 30 MeV to 75 MeV B ions have been presented. The B ion energies were varied in small steps in order to examine the energy dependence of the cross sections and the influence of multiple ionization on these cross sections. The experimental cross sections have been compared with the calculated ones obtained using the boron ion-induced L_p (p = 1–3) sub-shell ionization cross sections based on the PWBA and the ECPSSR models, X-ray emission rates based on the Dirac-Fock model, fluorescence and Coster-Kronig yields based on the Dirac-Hartree-Slater model. The significant differences observed between the measured and calculated values can be ascribed to multiple ionization effects caused by the incident boron ions in the target elements.

本文给出了30 MeV到75 MeV的B离子在Au和Bi中产生L x射线的实验截面。为了检验横截面的能量依赖性和多次电离对这些横截面的影响，B离子的能量以小幅度变化。将实验截面与基于PWBA和ECPSSR模型的硼离子诱导Lp （p = 1-3）亚壳电离截面、基于Dirac-Fock模型的x射线发射率、基于dirac - harree - slater模型的荧光和Coster-Kronig产率计算得到的计算截面进行了比较。实测值与计算值之间的显著差异可归因于靶元素中入射硼离子引起的多重电离效应。

引用次数: 0

A relativistic reinterpretation of the Bremsstrahlung isochromat spectroscopy of uranium materials 铀材料轫致等色光谱的相对论性重新解释

IF 1.5 4区物理与天体物理 Q2 SPECTROSCOPY

Journal of Electron Spectroscopy and Related Phenomena

Pub Date : 2025-12-09 DOI: 10.1016/j.elspec.2025.147577

J.G. Tobin , A. Kutepov

Utilizing the test systems αU, UBe₁₃, US and UTe, the unoccupied 5 f density of states is extracted from their Bremsstrahlung Isochromat Spectroscopy (BIS) based upon a jj picture of angular momentum coupling. Using a simple model and one set of parameters, it is found that it is possible to reconstruct the essence of the BIS results of all four test cases.

利用αU， UBe13， US和UTe测试系统，基于角动量耦合的jj图，从它们的轫致等色光谱（BIS）中提取了未占据态的5 f密度。使用一个简单的模型和一组参数，可以重建所有四个测试用例的BIS结果的本质。

引用次数: 0

Applications of auger electron spectroscopy in the chemical state analysis of copper and its oxides 俄歇电子能谱在铜及其氧化物化学状态分析中的应用

IF 1.5 4区物理与天体物理 Q2 SPECTROSCOPY

Journal of Electron Spectroscopy and Related Phenomena

Pub Date : 2025-12-01 DOI: 10.1016/j.elspec.2025.147578

Jeffrey D. Henderson , Mohammad Sabeti , Xuejie Li , Na Wang , Mehran Behazin , Mark C. Biesinger , James J. Noël , Sridhar Ramamurthy

Electron-induced Auger electron spectroscopy was successfully applied to differentiate copper species, such as metallic Cu, Cu₂O, CuO, and Cu(OH)₂. To do so, high-quality standard spectra were collected and their key parameters, including peak positions, widths, intensity ratios, and peak shapes, were examined to evaluate their effectiveness in chemical state identification. Average values and standard deviations were reported for each parameter. The results reveal sufficient spectral differences among Cu metal, Cu₂O, CuO, and Cu(OH)₂ to enable chemical fingerprinting, though no single parameter provided information sufficient for accurate speciation. Instead, a combination of spectral features must be used to enable reliable identification of these species. This approach was successfully applied to identify the chemical states of oxide layers formed on two different copper samples. The results from the Auger analyses were consistent with those from XPS measurements. This methodology was also applied to determine the presence of Cu₂O oxide inclusions in cold sprayed copper, and the results were consistent with previously published results from TEM, EELS, and electron diffraction studies. Compared to these techniques, Auger electron spectroscopy requires minimal sample preparation and offers high spatial and surface sensitivity.

利用电子诱导俄歇能谱成功地区分了金属Cu、Cu2O、CuO和Cu(OH)2等铜种。为此，收集了高质量的标准光谱，并检查了其关键参数，包括峰位置、宽度、强度比和峰形状，以评估其在化学状态鉴定中的有效性。报告了每个参数的平均值和标准差。结果显示，Cu金属、Cu2O、CuO和Cu(OH)2之间存在足够的光谱差异，可以实现化学指纹识别，尽管没有单一参数提供足够的信息来准确形成物种。相反，必须使用光谱特征的组合来可靠地识别这些物种。这种方法被成功地应用于鉴定两种不同铜样品上形成的氧化层的化学状态。俄歇分析的结果与XPS测量的结果一致。该方法也被用于确定冷喷涂铜中Cu2O氧化物夹杂物的存在，结果与先前发表的TEM， EELS和电子衍射研究结果一致。与这些技术相比，俄歇电子能谱需要最少的样品制备，并提供高的空间和表面灵敏度。

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引用次数: 0

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