The European Physical Journal D最新文献_第3页

Electron-initiated chemistry at the ambient water/air interface 环境水/空气界面的电子引发化学

IF 1.5 4区物理与天体物理 Q3 OPTICS

The European Physical Journal D

Pub Date : 2025-10-27 DOI: 10.1140/epjd/s10053-025-01081-z

Faith G. Pritchard, Dominik Habiger, Marnik Metting van Rijn, Juraj Fedor, Jan R. R. Verlet

The interaction of molecules with slow electrons can lead to profound chemical changes. So far, experimental probing of such interactions has been possible only with target systems in vacuum or in high energy environments where a range of processes and by-products can interfere with the electron-induced processes (e.g. in plasmas). Here, we demonstrate a method to cleanly deposit low-energy electrons onto an ambient water–air interface, with sufficient efficiency that its chemistry might be measured. Electrons are produced via the photoelectric effect at a photocathode and are driven onto an ambient water–air surface, to an anode. In traditional dissociation attachment experiments, high energy (> 10's eV) electrons excite water and oxygen molecules, leading to the detachment of secondary electrons. Monte Carlo simulations with homogeneous fields reveal that even with voltages tenfold of those used here, electrons > 2 eV are highly unlikely. This regime is similar to that of secondary electrons in traditional dissociative attachment experiments, which are those responsible for the observed electron-initiated chemistry. We follow the electron-initiated chemistry over time with a terephthalic acid dosimeter, which allows us to detect the presence of reactive products (OH•, e_(aq)^–) using in-situ fluorescence spectroscopy.

Graphical abstract

Electrons are injected into an aqueous solution using photoemission from an electrode and products monitored using a dosimeter

分子与慢电子的相互作用可以导致深刻的化学变化。到目前为止，这种相互作用的实验探测只能在真空或高能环境中的目标系统中进行，在这些环境中，一系列过程和副产品会干扰电子诱导的过程（例如在等离子体中）。在这里，我们展示了一种将低能电子干净地沉积到环境水-空气界面上的方法，其效率足以测量其化学性质。电子通过光电阴极的光电效应产生，并被驱动到周围的水-空气表面，形成阳极。在传统的离解附著实验中，高能量（> 10's eV）电子激发水分子和氧分子，导致二次电子脱离。均匀场的蒙特卡罗模拟显示，即使在这里使用的电压的十倍的情况下，电子>； 2ev是极不可能的。这一机制类似于传统离解附著实验中二次电子的机制，后者是观察到的电子引发化学的原因。随着时间的推移，我们用对苯二甲酸剂量计跟踪电子引发的化学反应，这使我们能够使用原位荧光光谱检测反应产物（OH•，e(aq) -）的存在。图示：利用电极的光电发射将电子注入水溶液，并用剂量计监测产物

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引用次数: 0

Correction: Precision physics of simple atomic systems: insights from PSAS 2024 修正：简单原子系统的精确物理学：来自PSAS 2024的见解

IF 1.5 4区物理与天体物理 Q3 OPTICS

The European Physical Journal D

Pub Date : 2025-10-23 DOI: 10.1140/epjd/s10053-025-01065-z

Paolo Crivelli, Savely Karshenboim, Daniel Kienzler, Fabian Schmid

引用次数: 0

Exact solution of 1D Euler–Poisson equations describing nonlinear Langmuir oscillations in cold bounded plasmas 描述冷有界等离子体非线性朗缪尔振荡的一维欧拉-泊松方程的精确解

IF 1.5 4区物理与天体物理 Q3 OPTICS

The European Physical Journal D

Pub Date : 2025-10-23 DOI: 10.1140/epjd/s10053-025-01078-8

Gopal Basak, Chandan Maity

Nonlinear Langmuir oscillations in a cold bounded plasma of finite resistivity have been analyzed. Without recourse to the Lagrangian coordinates, a class of exact space-time-dependent solution of the governing 1D Euler–Poisson equations has been obtained. Under well-defined boundary and initial conditions, a piecewise linear solution of the equations on a segment is constructed. The method outlined here for solving the equations is expected to be fruitfully applied in many branches of nonlinear physics having similar model.

Spatio-temporal evolution of electron fluid velocity

分析了有限电阻率冷有界等离子体中的非线性朗缪尔振荡。在不依赖拉格朗日坐标的情况下，得到了一维欧拉-泊松方程的一类时空相关精确解。在边界和初始条件良好的条件下，构造了方程在段上的分段线性解。本文提出的求解方程的方法有望在具有类似模型的许多非线性物理分支中得到有效的应用。电子流体速度的时空演化

引用次数: 0

Characterizing the generalized Einstein–Podolsky–Rosen state and extensions 描述广义Einstein-Podolsky-Rosen态及其扩展

IF 1.5 4区物理与天体物理 Q3 OPTICS

The European Physical Journal D

Pub Date : 2025-10-22 DOI: 10.1140/epjd/s10053-025-01082-y

Rashi Adhikari, Mohd Shoaib Qureshi, Tabish Qureshi

In their seminal paper, Einstein, Podolsky, and Rosen (EPR) had introduced a momentum-entangled state for two particles. That state, referred to as the EPR state, has been widely used in studies on entangled particles with continuous degrees of freedom. Later that state was generalized to a form that allows varying degree of entanglement, known as the generalized EPR state. In a suitable limit it reduces to the EPR state. The generalized EPR state is theoretically analyzed here and its entanglement quantified in terms of a recently introduced generalized entanglement measure. This state can also be applied to entangled photons produced from spontaneous parametric down-conversion (SPDC). The present analysis is then used in quantifying the entanglement of photons produced from the SPDC process, in terms of certain experimental parameters. A comparison is also made with the Schmidt number, which is normally used as an entanglement measure in such situations. A procedure for experimentally determining the entanglement of SPDC photons has also been described. Furthermore, an additional state exhibiting non-Gaussian entanglement has been examined, and its entanglement has been quantified.

在他们的开创性论文中，爱因斯坦、波多尔斯基和罗森（EPR）引入了两个粒子的动量纠缠态。这种状态被称为EPR状态，已广泛应用于具有连续自由度的纠缠粒子的研究中。后来，这种状态被推广为一种允许不同程度纠缠的形式，称为广义EPR状态。在适当的极限下，它降低到EPR状态。本文对广义EPR态进行了理论分析，并用最近引入的广义纠缠度量对其纠缠度进行了量化。这种状态也可以应用于自发参数下转换（SPDC）产生的纠缠光子。然后，根据某些实验参数，将本分析用于量化SPDC过程中产生的光子纠缠。还与施密特数进行了比较，施密特数通常被用作这种情况下的纠缠度量。实验确定SPDC光子纠缠的过程也被描述。此外，还研究了一种表现出非高斯纠缠的附加态，并对其纠缠进行了量化。

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引用次数: 0

Investigation of radio-frequency sheath structure in electronegative plasma with Cairns–Tsallis electron distribution 电负性等离子体射频鞘层结构的Cairns-Tsallis电子分布研究

IF 1.5 4区物理与天体物理 Q3 OPTICS

The European Physical Journal D

Pub Date : 2025-10-18 DOI: 10.1140/epjd/s10053-025-01076-w

Mohamed Bouzraa, Abdelhak Missaoui, Morad El Kaouini, Mohamed El Bojaddaini, Hassan Chatei

This study investigates the behavior of a radio-frequency (RF) plasma sheath comprising electrons, positive ions, and negative ions. The sheath structure is analyzed numerically using a one-dimensional hydrodynamic model coupled to an equivalent circuit. In this model, electrons are described by a Cairns–Tsallis distribution, which accounts for both non-extensive and non-thermal characteristics. Positive ions are modeled as a fluid, while negative ions follow a Boltzmann distribution. An equivalent circuit, consisting of a diode, a capacitor, and a current source connected in parallel, is used to describe the spatio-temporal evolution of the RF sheath properties. The results show that as the electronegativity parameter decreases, the sheath structure becomes significantly influenced by the non-extensivity parameter, the non-thermality parameter, the current amplitude, the electron to negative ion temperature ratio, and the current frequency.

Graphical abstract

本研究探讨了由电子、正离子和负离子组成的射频等离子体鞘层的行为。采用一维流体力学模型耦合等效电路对护套结构进行了数值分析。在这个模型中，电子是用凯恩斯-萨利斯分布来描述的，它既说明了非扩展特性，也说明了非热特性。正离子被建模为流体，而负离子遵循玻尔兹曼分布。一个等效电路，由一个二极管，一个电容器和一个并联的电流源组成，用来描述射频护套特性的时空演变。结果表明：随着电负性参数的减小，鞘层结构受非扩张性参数、非热性参数、电流幅值、电子与负离子温度比和电流频率的影响显著；图形抽象

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引用次数: 0

A cryogenic Paul trap for probing the nuclear isomeric excited state (^{229text {m}})Th(^{3+}) 探测核异构体激发态的低温保罗阱(^{229text {m}}) [j](^{3+})

IF 1.5 4区物理与天体物理 Q3 OPTICS

The European Physical Journal D

Pub Date : 2025-10-17 DOI: 10.1140/epjd/s10053-025-01071-1

Daniel Moritz, Kevin Scharl, Markus Wiesinger, Georg Holthoff, Tamila Teschler, Mahmood I. Hussain, José R. Crespo López-Urrutia, Timo Dickel, Shiqian Ding, Christoph E. Düllmann, Eric R. Hudson, Sandro Kraemer, Lilli Löbell, Christoph Mokry, Jörg Runke, Benedict Seiferle, Lars von der Wense, Florian Zacherl, Peter G. Thirolf

While laser excitation of the nuclear isomeric transition in (^{229})Th has been recently achieved for thorium atoms embedded in large-bandgap crystals, laser excitation and characterization of the nuclear transition in trapped (^{229})Th(^{3+}) ions has not yet been accomplished. To address these experiments, a cryogenic Paul trap setup has been designed, built, and commissioned at LMU Munich. Here, we present the specifications of the new experimental platform and demonstrate its successful operation, showing the extraction, subsequent ion guiding, mass purification, and trapping of (^{229})Th(^{3+}) and (^{229text {m}})Th(^{3+}) ions from a newly designed buffer-gas stopping cell as well as of (^{88})Sr(^{+}) ions from laser ablation of a solid target. Further, we show sympathetic laser cooling of (^{229text {(m)}})Th(^{3+}) by Doppler-cooled (^{88})Sr(^{+}) ions and the formation of mixed-species Coulomb crystals.

虽然最近已经实现了对嵌入在大带隙晶体中的钍原子在(^{229}) Th中的核异构体跃迁的激光激发，但尚未完成对捕获(^{229}) Th (^{3+})离子的核跃迁的激光激发和表征。为了解决这些实验，在慕尼黑大学设计、建造和调试了一个低温保罗陷阱装置。在这里，我们介绍了新实验平台的规格，并演示了其成功的操作，展示了从新设计的缓冲气体停止池中提取(^{229}) Th (^{3+})和(^{229text {m}}) Th (^{3+})离子，以及激光烧蚀固体目标的(^{88}) Sr (^{+})离子的过程。此外，我们还发现了通过多普勒冷却的(^{88}) Sr (^{+})离子对(^{229text {(m)}}) Th (^{3+})的共感激光冷却和混合种库仑晶体的形成。

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引用次数: 0

Theoretical and experimental investigation of UV–Vis absorption spectra in plasma-activated water 等离子体活化水中UV-Vis吸收光谱的理论与实验研究

IF 1.5 4区物理与天体物理 Q3 OPTICS

The European Physical Journal D

Pub Date : 2025-10-14 DOI: 10.1140/epjd/s10053-025-01074-y

Nilton F. AzevedoNeto, Orisson P. Gomes, Felipe S. Miranda, Paulo N. Lisboa-Filho, Augusto Batagin-Neto, Didier Bégué, Rodrigo S. Pessoa

This research comprehensively examines the physicochemical and optical properties of plasma-activated water (PAW) produced by a serially associated dielectric barrier discharge (DBD) and gliding arc plasma jet (GAPJ) system. Experimental UV–Vis spectroscopy identified prominent absorption bands attributed to reactive oxygen and nitrogen species (RONS) such as nitrite (NO₂⁻), nitrate (NO₃⁻), hydrogen peroxide (H₂O₂), nitrous acid (HNO₂), and nitric acid (HNO₃). To precisely interpret the complex and overlapping experimental spectra, density functional theory (DFT) simulations were utilized to model electronic transitions. These theoretical findings crucially revealed the influence of protonation on the optical features, showing blue-shifted bands for ionic species and red-shifted bands for their protonated forms.

Graphic abstract

Integrated UV-Vis and TD-DFT analysis of Plasma-Activated Water (PAW) from a serial DBD-GAPJ system, highlighting the decisive influence of protonation on the optical features of RONS

本研究全面考察了介电阻挡放电（DBD）和滑动电弧等离子体射流（GAPJ）串联相关系统产生的等离子体活化水（PAW）的物理化学和光学特性。实验紫外-可见光谱发现，亚硝酸盐（NO2−）、硝酸盐（NO3−）、过氧化氢（H2O2）、亚硝酸（HNO2）和硝酸（HNO3）等活性氧和氮物质（RONS）的显著吸收带。为了精确解释复杂和重叠的实验光谱，利用密度泛函理论（DFT）模拟电子跃迁。这些理论发现至关重要地揭示了质子化对光学特性的影响，显示了离子种类的蓝移带和质子化形式的红移带。图摘要对连续DBD-GAPJ系统的等离子体活化水（PAW）进行了UV-Vis和TD-DFT综合分析，突出了质子化对RONS光学特性的决定性影响

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引用次数: 0

The energy dependence of the rotational relaxation process in the collision between excited state H2 X1Σg+(v = 1, J = 9, 11) and CO 激发态H2 X1Σg+(v = 1, J = 9,11)与CO碰撞时旋转弛豫过程的能量依赖

IF 1.5 4区物理与天体物理 Q3 OPTICS

The European Physical Journal D

Pub Date : 2025-10-08 DOI: 10.1140/epjd/s10053-025-01075-x

Kai Wang, Zhong Liu, Shuying Wang, Xinru Li

The collisional relaxation between excited H₂ and CO is investigated utilizing the stimulated Raman pumping (SRP) technique to achieve the excited state of H₂ X¹Σ_g⁺(v = 1, J = 9, 11). The excitation to the H₂(1, 9) (E = 5900 cm⁻¹) and H₂(1, 11) (E = 6245 cm⁻¹) energy levels were confirmed using coherent anti-Stokes Raman spectroscopy (CARS). At a sample cell temperature of 298 ± 1 K, the collisional depopulation rate of H₂(1, J) molecules was obtained by fitting the graph of CARS signal intensity versus delay time. The collisional transfer rate coefficients between excited H₂(1, J) molecules and CO, under varying excitation energy conditions, were calculated using the Stern–Volmer equation. For J = 9, the rate coefficients were k_J=9(CO) = (2.36 ± 0.55) × 10^–14 cm³ s⁻¹ and k_J=9(H₂) = (0.89 ± 0.29) × 10^–14 cm³ s⁻¹, while for J = 11, they were k_J=11(CO) = (1.90 ± 0.36) × 10^–14 cm³ s⁻¹ and k_J=11(H₂) = (0.65 ± 0.19) × 10^–14 cm³ s⁻¹. It was observed that the collisional transfer rate coefficient decreased with increasing excitation energy. When the cell temperature was varied from 298 to 475 K, the collisional transfer rate coefficients for the H₂-CO system increased nonlinearly with temperature. Analysis of the time-resolved CARS spectra for individual rotational levels of H₂(1, J) demonstrated that multi-quantum transitions with ΔJ = 4 dominated during relaxation. Furthermore, the higher excitation energy is linked to the longer relaxation times to achieve equilibrium. Elevating the temperature of the cell significantly accelerated the relaxation process, and the rotation-rotation (R-R) energy transfer process exhibited high-temperature sensitivity. The time evolution of the rotational temperature for H₂(1, 9) molecules was determined using the Boltzmann rotational distribution. The rotational temperature decayed exponentially, eventually stabilizing within the 362–379 K range.

Graphical Abstract

利用受激拉曼泵浦（SRP）技术研究了H2与CO之间的碰撞弛豫，以获得H2 X1Σg+(v = 1, J = 9,11)的激发态。利用相干反斯托克斯拉曼光谱（CARS）证实了H2(1,9) （E = 5900 cm−1）和H2(1,11) （E = 6245 cm−1）能级的激发。在样品细胞温度为298±1 K时，通过拟合CARS信号强度随延迟时间的变化曲线，得到H2（1,j）分子的碰撞失居率。利用Stern-Volmer方程计算了不同激发能条件下H2（1， J）分子与CO的碰撞传递速率系数。J = 9,系数kJ = 9 (CO) =(2.36±0.55)×10 - 14立方厘米−1和kJ = 9 (H2) =(0.89±0.29)×10 - 14立方厘米−1,而对于J = 11,他们kJ = 11 (CO) =(1.90±0.36)×10 - 14立方厘米−1和kJ = 11 (H2) =(0.65±0.19)×10 - 14立方厘米−1。结果表明，碰撞传递率系数随激发能的增大而减小。当电池温度在298 ~ 475 K范围内变化时，H2-CO体系的碰撞传递速率系数随温度呈非线性增加。对H2（1， J）各个旋转能级的时间分辨CARS光谱分析表明，在弛豫过程中，ΔJ = 4的多量子跃迁占主导地位。此外，较高的激发能与较长的松弛时间相关联，以达到平衡。升高细胞温度可显著加速弛豫过程，旋转-旋转（R-R）能量传递过程表现出高温敏感性。利用玻尔兹曼旋转分布确定了H2（1,9）分子的旋转温度随时间的变化。旋转温度呈指数衰减，最终稳定在362 ~ 379 K范围内。图形抽象

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引用次数: 0

Cellular DNA damage induced by low-energy (0–20 eV) electrons 低能电子（0-20 eV）诱导的细胞DNA损伤

IF 1.5 4区物理与天体物理 Q3 OPTICS

The European Physical Journal D

Pub Date : 2025-10-07 DOI: 10.1140/epjd/s10053-025-01069-9

Léon Sanche

In this article, different types of experiments are suggested to further investigate the interactions of low-energy (0–20 eV) electrons (LEEs) with DNA under conditions increasingly closer to those of living cells. Their feasibility is illustrated by describing the methods involved, together with recently obtained results. These include LEE-impact experiments on plasmid films surrounded by water and oxygen or modified to account for the presence of amino acids bound to DNA in the nucleus. Measurements of cellular behavior due to DNA damage induced by LEEs generated outside or inside the cell are also described. The former shows a direct correspondence between the decay of core-excited transient anions into destructive channels and the decrease of cellular functionality. Using femtosecond lasers, it is also possible to directly probe the action of LEEs in living cells. In these experiments, the LEE energy distribution in the cellular medium and the time required for the biological response must be considered. The generation of LEE distributions is discussed in terms of the present limit of stochastic model calculations to include the quantum behavior of LEEs, and the biological response, which requires considerable knowledge of the molecular biology involved to reach a detailed interpretation of the dose–response curves. An improved fundamental understanding of the action of LEEs in the cell nucleus is expected to assist in the targeting of radiosensitizing molecules toward the most vulnerable sites in DNA and hence improve chemoradiation therapy.

Graphical Abstract

Analysis of cell behavior following low energy electron (LEE) impact from a direct source and that generated from a femtosecond laser

本文建议在越来越接近活细胞的条件下，进行不同类型的实验来进一步研究低能电子（0-20 eV）与DNA的相互作用。通过描述所涉及的方法以及最近获得的结果，说明了它们的可行性。这些实验包括对被水和氧包围的质粒膜进行LEE-impact实验，或者对其进行修饰以解释细胞核中与DNA结合的氨基酸的存在。还描述了由细胞内外产生的LEEs引起的DNA损伤引起的细胞行为的测量。前者显示了核激发的瞬态阴离子向破坏通道的衰变与细胞功能的下降之间的直接对应关系。利用飞秒激光，还可以直接探测活细胞中LEEs的作用。在这些实验中，必须考虑细胞介质中的LEE能量分布和生物反应所需的时间。根据目前随机模型计算的极限来讨论LEE分布的产生，以包括LEE的量子行为和生物反应，这需要相当多的分子生物学知识来达到剂量-反应曲线的详细解释。提高对LEEs在细胞核中的作用的基本理解有望有助于将放射致敏分子靶向DNA中最脆弱的部位，从而改善放化疗。图解【摘要】分析了直接源和飞秒激光产生的低能电子（LEE）冲击后的电池行为

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引用次数: 0

Momentum flux measurements in a negative ion beam for fusion research 用于核聚变研究的负离子束流动量通量测量

IF 1.5 4区物理与天体物理 Q3 OPTICS

The European Physical Journal D

Pub Date : 2025-10-07 DOI: 10.1140/epjd/s10053-025-01053-3

Thomas Trottenberg, Alexander Spethmann, Loïc Schiesko, Christian Wimmer, Holger Kersten, Ursel Fantz

A new method for determining the particle flux density in the beam of a neutral beam injector (NBI) for magnetically confined fusion plasmas is presented. The method uses a force probe to measure the momentum transfer from beam particles to a small target and has been applied at the BATMAN experimental facility at the MPI Garching. The experiments presented in this report are performed in the non-neutralized negative ion beam. It is found that the force measured at a distance of 1.4 m from the negative ion source correlates well with the momentum flux that is calculated from the ion energy and the averaged extracted ion current density.

Schematic of the force-probe diagnostic for momentum-flux measurements in the negative hydrogenion beam at the BATMAN facility. A water-cooled shield with a 5 mm aperture limits the beam spot on an L-shaped tungsten target mounted on an interferometric cantilever probe, enabling charge-independent local flux determination 1.4m downstream of the source

提出了一种测定中性束注入器（NBI）束流中粒子通量密度的新方法。该方法使用一个力探针来测量从束粒子到小目标的动量转移，并已在MPI Garching的BATMAN实验设施中应用。本报告中的实验是在未中和的负离子束流中进行的。在距离负离子源1.4 m处测得的力与由离子能量和提取的平均离子电流密度计算得到的动量通量具有良好的相关性。在BATMAN设施中用于负氢离子束动量通量测量的力探针诊断示意图。一个孔径为5mm的水冷罩将光束光斑限制在安装在干涉悬臂式探头上的l形钨靶上，从而能够在源下游1.4m处进行与电荷无关的局部通量测定

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引用次数: 0