Journal of Electron Spectroscopy and Related Phenomena最新文献

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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

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

引用次数: 0

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

引用次数: 0

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

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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

引用次数: 0

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

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

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