The European Physical Journal D最新文献

{"title":"The energy dependence of the rotational relaxation process in the collision between excited state H2 X1Σg+(v = 1, J = 9, 11) and CO","authors":"Kai Wang,&nbsp;Zhong Liu,&nbsp;Shuying Wang,&nbsp;Xinru Li","doi":"10.1140/epjd/s10053-025-01075-x","DOIUrl":"10.1140/epjd/s10053-025-01075-x","url":null,"abstract":"<div><p>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⁺(<i>v</i> = 1, <i>J</i> = 9, 11). The excitation to the H₂(1, 9) (<i>E</i> = 5900 cm⁻¹) and H₂(1, 11) (<i>E</i> = 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, <i>J</i>) molecules was obtained by fitting the graph of CARS signal intensity versus delay time. The collisional transfer rate coefficients between excited H₂(1, <i>J</i>) molecules and CO, under varying excitation energy conditions, were calculated using the Stern–Volmer equation. For <i>J</i> = 9, the rate coefficients were <i>k</i>_<i>J</i>=9(CO) = (2.36 ± 0.55) × 10^–14 cm³ s⁻¹ and <i>k</i>_<i>J</i>=9(H₂) = (0.89 ± 0.29) × 10^–14 cm³ s⁻¹, while for <i>J</i> = 11, they were <i>k</i>_<i>J</i>=11(CO) = (1.90 ± 0.36) × 10^–14 cm³ s⁻¹ and <i>k</i>_<i>J</i>=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,<i> J</i>) demonstrated that multi-quantum transitions with Δ<i>J</i> = 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.</p><h3>Graphical Abstract</h3>\u0000<div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":789,"journal":{"name":"The European Physical Journal D","volume":"79 10","pages":""},"PeriodicalIF":1.5,"publicationDate":"2025-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145256170","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":"Cellular DNA damage induced by low-energy (0–20 eV) electrons","authors":"Léon Sanche","doi":"10.1140/epjd/s10053-025-01069-9","DOIUrl":"10.1140/epjd/s10053-025-01069-9","url":null,"abstract":"<div><p>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.</p><h3>Graphical Abstract</h3><div><figure><div><div><picture><source><img></source></picture></div><div><p>Analysis of cell behavior following low energy electron (LEE) impact from a direct source and that generated from a femtosecond laser</p></div></div></figure></div></div>","PeriodicalId":789,"journal":{"name":"The European Physical Journal D","volume":"79 10","pages":""},"PeriodicalIF":1.5,"publicationDate":"2025-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145256569","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":"Momentum flux measurements in a negative ion beam for fusion research","authors":"Thomas Trottenberg,&nbsp;Alexander Spethmann,&nbsp;Loïc Schiesko,&nbsp;Christian Wimmer,&nbsp;Holger Kersten,&nbsp;Ursel Fantz","doi":"10.1140/epjd/s10053-025-01053-3","DOIUrl":"10.1140/epjd/s10053-025-01053-3","url":null,"abstract":"<p>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.</p><p>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 <i>L</i>-shaped tungsten target mounted on an interferometric cantilever probe, enabling charge-independent local flux determination 1.4<i>m</i> downstream of the source</p>","PeriodicalId":789,"journal":{"name":"The European Physical Journal D","volume":"79 10","pages":""},"PeriodicalIF":1.5,"publicationDate":"2025-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjd/s10053-025-01053-3.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145256568","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":"The measurement problem in liquid NMR quantum computers","authors":"O. Jalili,&nbsp;M. Heidari Adl","doi":"10.1140/epjd/s10053-025-01072-0","DOIUrl":"10.1140/epjd/s10053-025-01072-0","url":null,"abstract":"<p>With the quantum state diffusion measurement theory (QSD), the measurement problem in liquid nuclear magnetic resonance (NMR) quantum computers was addressed and then it was shown that due to stochastical fluctuations, the measured magnetic moment value is comparable to noise for long times. Therefore, we suggested that the measurement time should be short to distinguish signal from noise.</p><p>QSD in NMR quantum computers.</p>","PeriodicalId":789,"journal":{"name":"The European Physical Journal D","volume":"79 10","pages":""},"PeriodicalIF":1.5,"publicationDate":"2025-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjd/s10053-025-01072-0.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145230501","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":"Interaction of 25 eV electrons with DNA constituents: XPS analysis of calf thymus DNA, nucleosides, and nucleobases","authors":"João Pereira-da-Silva,&nbsp;Hao Yu,&nbsp;Bo-An Chen,&nbsp;Pitambar Sapkota,&nbsp;Filipe Ferreira da Silva,&nbsp;Sylwia Ptasińska","doi":"10.1140/epjd/s10053-025-01068-w","DOIUrl":"10.1140/epjd/s10053-025-01068-w","url":null,"abstract":"<div><p>Understanding the interactions of secondary electrons generated by ionizing radiation provides a fundamental basis for developing strategies in cancer therapy. In this study, we investigated the interactions of 25 eV low-energy electrons (LEEs) with calf thymus DNA and its constituents, four types of nucleosides and nucleobases, using X-ray photoelectron spectroscopy (XPS). Based on the acquisition and analysis of core-level spectra (O 1s, C 1s, N 1s, and P 2p) in DNA, structural changes induced by 25 eV electrons suggest potential site- and base-specific selectivity. These changes may involve hydroxyl (C–OH) group release from the sugar moiety, cleavage of C–N bonds (likely corresponding to N-glycosidic linkages), and phosphate backbone damage in calf thymus DNA. Among the four nucleosides, thymidine and guanosine showed more evident structural modifications, while cytidine and adenosine were relatively stable. In addition, nucleosides displayed greater susceptibility to LEE-induced structural changes than their corresponding nucleobases. This study reveals the selective damage mechanisms of LEEs on various DNA constituents, which may provide mechanistic insights for future developments in precision cancer therapy based on molecular-level damage.</p><h3>Graphical abstract</h3><div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":789,"journal":{"name":"The European Physical Journal D","volume":"79 10","pages":""},"PeriodicalIF":1.5,"publicationDate":"2025-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjd/s10053-025-01068-w.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145230500","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":"Highly accurate calculation of the hyperpolarizabilities of hydrogenic atoms interacting with screened Coulomb potentials: a variation–perturbation approach","authors":"Santu Ghosh,&nbsp;Arijit Ghoshal","doi":"10.1140/epjd/s10053-025-01073-z","DOIUrl":"10.1140/epjd/s10053-025-01073-z","url":null,"abstract":"<p>Variational expressions for functionals yielding the second-order and fourth-order corrections to the nondegenerate eigenenergies of a Hamiltonian subject to a given perturbation have been derived. Discrete basis sets consisting of the suitably chosen eigenfunctions of the unperturbed Hamiltonian along with a nonlinear variational parameter can be used to evaluate the stationary functional quite accurately. The method has been applied conveniently to calculate the dipole hyperpolarizabilities of the hydrogenic atoms interacting with screened Coulomb potentials (SCP) quite accurately. Three SCPs are considered, namely the static screened Coulomb potential, the exponential cosine screened Coulomb potential and the generalized exponential cosine screened Coulomb potential. It is found that a basis set consisting of 20 eigenfunctions of the p-states of the hydrogenic atoms yields stationary functional corresponding to the second-order correction to the energy, whereas a basis set consisting of 20 d-state eigenfunctions and 19 s-state eigenfunctions of the hydrogenic atoms produces stationary functional corresponding to the fourth-order correction to the energy. Moreover, the stationary values of the functionals are highly accurate (up to 14th place of decimal) and converge rapidly with the increase in the number of terms in the basis sets.</p>","PeriodicalId":789,"journal":{"name":"The European Physical Journal D","volume":"79 10","pages":""},"PeriodicalIF":1.5,"publicationDate":"2025-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145230502","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":"The effect of space restriction on the bonding and vibrational properties of H(_{2}^{+}) molecular ion","authors":"Claude Le Sech,&nbsp;Arup Banerjee","doi":"10.1140/epjd/s10053-025-01062-2","DOIUrl":"10.1140/epjd/s10053-025-01062-2","url":null,"abstract":"<p>When the space surrounding an atom or molecule is restricted, its electron density is modified compared to its unrestricted counterpart, which further alters its physical and chemical properties. To model the effect of space restriction, or confinement, on atoms and molecules, often the hard-boundary condition is employed to solve the corresponding Schrödinger equation. In the present work, we analyze the modifications in a chemical bond when the space surrounding the molecule is restricted such that some part of the space is forbidden to the electrons. To this end, we choose the simplest hydrogen molecular ion H<span>(_{2}^{+})</span>, in the presence of an external hard-sphere simulating the restriction of space available to the electrons due to Pauli exclusion by an atom close to the molecule. The hard-sphere is moved along the molecular axis and the axis transverse to it to study the changes in the ground-state energy, stretching frequency, kinetic, and potential energies of an H<span>(_{2}^{+})</span> molecule. For this purpose, we employ a variational approach using a suitably constructed energy estimator that goes beyond the Born–Oppenheimer approximation. We find that as the sphere moves closer to the molecule along the molecular axis, the ground-state energy and the vibrational frequencies get enhanced. On the other hand, for the same case, the potential energy decreases, and the kinetic energy increases. When the sphere moves along the axis transverse to the molecular axis, the changes in the energy and vibrational frequencies show similar trends; however, the magnitude of the changes is significantly smaller than in the corresponding molecular axis case. For the transverse case, both potential and kinetic energies get enhanced marginally. These results demonstrate that the axial approach of the hard surface is more efficient in inducing a bond breaking of the H<span>(_{2}^{+})</span> molecular ion. The shift of the electron bond by the external sphere explains these results.</p>","PeriodicalId":789,"journal":{"name":"The European Physical Journal D","volume":"79 9","pages":""},"PeriodicalIF":1.5,"publicationDate":"2025-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjd/s10053-025-01062-2.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145210934","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":"Density matrix analysis of systems with periodic Hamiltonians","authors":"Soham Sen,&nbsp;Manjari Dutta,&nbsp;Sunandan Gangopadhyay","doi":"10.1140/epjd/s10053-025-01070-2","DOIUrl":"10.1140/epjd/s10053-025-01070-2","url":null,"abstract":"<p>In this work, we consider simple systems that are governed by Hamiltonians with time periodicity. Our analysis is mainly focused on the density matrix approach and aims to solve the von Neumann equation of motion from which one can extract the state of the system when the system is in a pure state. We start our analysis with the standard Rabi-oscillation problem. We consider a density matrix corresponding to the entire model system and solve the von Neumann equation of motion. We have then made use of the Lewis-Reisenfeld invariant approach and arrived at the exact same result, which implies that the density matrix of the system can indeed be identified with the Lewis invariant. Then, we consider a two-level system with a constant magnetic field in the <i>z</i>-direction and a time-dependent magnetic field in the <i>x</i>-direction. We solve the von Neumann equation of motion for this system and calculate the various coherence measures, and plot them to investigate the time dependence and reliability of different coherence measures.</p><p>Correspondence between the density operator and the Lewis invariant operator of the system</p>","PeriodicalId":789,"journal":{"name":"The European Physical Journal D","volume":"79 9","pages":""},"PeriodicalIF":1.5,"publicationDate":"2025-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145210651","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":"Elastic and charge transfer cross sections for low to ultralow (textrm{H}(1s)+textrm{H} ^{+}) collisions: quantal and semiclassical calculations","authors":"Mykhaylo Khoma","doi":"10.1140/epjd/s10053-025-01059-x","DOIUrl":"10.1140/epjd/s10053-025-01059-x","url":null,"abstract":"<p>The elastic scattering and resonant charge transfer differential and integral cross sections in <span>(textrm{H}(1s) + mathrm{H^+})</span> collisions are computed for the center-of-mass energy range of <span>(10^{-10}-10)</span> eV. Fully quantal and semiclassical approaches are utilized in these calculations. The reliability of the semiclassical approximation for very low collision energies is discussed. The results are compared with available data from the literature.</p>","PeriodicalId":789,"journal":{"name":"The European Physical Journal D","volume":"79 9","pages":""},"PeriodicalIF":1.5,"publicationDate":"2025-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145210650","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":"Kinetic Alfvén solitary waves in multi-species magnetoplasma with Tsallis-distributed electrons and positrons","authors":"M. Sarker,&nbsp;M. M. Hasan,&nbsp;M. G. Shah,&nbsp;M. R. Hossen,&nbsp;A. A. Mamun","doi":"10.1140/epjd/s10053-025-01063-1","DOIUrl":"10.1140/epjd/s10053-025-01063-1","url":null,"abstract":"<p>The nonlinear dynamics of plasma waves in multi-species magnetized systems is of great importance for understanding energy transport and particle interactions in both astrophysical and laboratory environments. This study investigates heavy ion-acoustic kinetic Alfvén solitary waves (HIAKASWs) in a magnetized plasma composed of inertial thermal heavy ions and non-extensive electron–positron pairs. Using the reductive perturbation method, we derive both the Korteweg–de Vries (K-DV) and modified Korteweg–de Vries (MK-DV) equations, which capture the balance between dispersion and nonlinearity, and analyze their soliton solutions under different plasma conditions. The electron and positron populations are described by Tsallis non-extensive statistics, allowing exploration of deviations from Maxwellian behavior. The analysis reveals that the K-DV equation admits both compressive and rarefactive solitary structures, while the higher-order MK-DV formulation supports only compressive modes. Parametric investigations demonstrate that heavy ion thermal pressure and inertia play a dominant role in shaping wave amplitude and width compared to electron and positron effects. The results highlight the influence of non-extensivity, magnetic field strength, and propagation angle on solitary wave characteristics, with implications for plasma dynamics in astrophysical and laboratory environments.</p><p>The plots highlight the effects of <span>(beta )</span>, <span>(gamma )</span>, and heavy ion density on dispersion, nonlinearity, and electrostatic potential of K-DV and MK-DV solitons, relevant to astrophysical and laboratory plasmas.</p>","PeriodicalId":789,"journal":{"name":"The European Physical Journal D","volume":"79 9","pages":""},"PeriodicalIF":1.5,"publicationDate":"2025-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145145402","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}