Collisions of low-energy antiprotons with molecular hydrogen: ionization, excitation and stopping power

Shell-to-shell ionization cross sections of antiprotons, H$^{+}$, He$^{2+}$, Be$^{4+}$, C$^{6+}$ and O$^{8+}$ on H, He, Li, Be, B, C, N, O, F, Ne, P, S and Ar neutral atoms

Total ionization cross sections of H, He, Li, Be, B, C, N, O, F, Ne, P, S and Ar neutral atoms by impact of antiprotons, H^{+}, He^{2+}, Be^{4+}, % C^{6+} and O^{8+}. were calculated using the CDWEIS (continuum distorted wave -Eikonal Initial state) theoretical method. Cross section depending on of initial the quantum numbers n and l are reported in Tables for a range of impact energies covering from 100 keV/amu to 10 MeV/amu

Full two-electron calculations of antiproton collisions with molecular hydrogen

Total cross sections for single ionization and excitation of molecular hydrogen by antiproton impact are presented over a wide range of impact energy from 1 keV to 6.5 MeV. A nonpertubative time-dependent close-coupling method is applied to fully treat the correlated dynamics of the electrons. Good agreement is obtained between the present calculations and experimental measurements of single-ionization cross sections at high energies, whereas some discrepancies with the experiment are found around the maximum. The importance of the molecular geometry and a full two-electron description is demo…

Low and intermediate energy stopping power of protons and antiprotons in canonical targets

In this work we propose a non-perturbative approximation to the electronic stopping power based on the central screened potential of a projectile moving in a free electron gas, by Nagy and Apagyi. We used this model to evaluate the energy loss of protons and antiprotons in ten solid targets: Cr, C, Ni, Be, Ti, Si, Al, Ge, Pb, Li and Rb. They were chosen as canonicals because they have reliable values of the Seitz radio, rS=1.48-5.31 a.u., which cover most of the possible metallic solids. Present low velocity results agree well with the experimental data for both proton and antiproton impact. O…

Ionization of helium by slow antiproton impact: total and differential cross sections

We theoretically investigate the single and double ionization of the He atom by antiproton impact for projectile energies ranging from $3$~keV up to $1000$~keV. We obtain accurate total cross sections by directly solving the fully correlated two-electron time-dependent Schrödinger equation and by performing classical trajectory Monte-Carlo calculations. The obtained quantum-mechanical results are in excellent agreement with the available experimental data. Along with the total cross sections, we also present the first fully \textit{ab initio} doubly differential data for single ionization at 1…

Ionization of hydrogen and hydrogenic ions by antiprotons

Presented here is a description of the ionization of hydrogen and hydrogenic ions by antiproton-impact, based on very large scale numerical solutions of the time-dependent Schrödinger equation in three spatial dimensions and on analysis of the topology of the electronic eigenenergy surfaces in the plane of complex internuclear distance. Comparison is made with other theories and very recent measurements.

Collisions of antiprotons with hydrogen molecular ions

Time-dependent close-coupling calculations of the ionization and excitation cross section for antiproton collisions with molecular hydrogen ions are performed in an impact-energy range from 0.5 keV to 10 MeV. The Born-Oppenheimer and Franck-Condon approximations as well as the impact parameter method are applied in order to describe the target molecule and the collision process. It is shown that three perpendicular orientations of the molecular axis with respect to the trajectory are sufficient to accurately reproduce the ionization cross section calculated by [Sakimoto, Phys. Rev. A 71, 06270…

Classical trajectory Monte Carlo model calculations for the antiproton-induced ionization of atomic hydrogen at low impact energy

The three-body dynamics of the ionization of the atomic hydrogen by 30 keV antiproton impact has been investigated by calculation of fully differential cross sections (FDCS) using the classical trajectory Monte Carlo (CTMC) method. The results of the calculations are compared with the predictions of quantum mechanical descriptions: The semi-classical time-dependent close-coupling theory, the fully quantal, time-independent close-coupling theory, and the continuum-distorted-wave-eikonal-initial-state model. In the analysis particular emphasis was put on the role of the nucleus-nucleus (NN) inte…

裸离子和反质子引起原子电离的CDW-EIS计算

Distorted-Wave calculations of atomic ionization by bare ions and antiprotons

本文在CDW-EIS模型下计算了裸离子和反质子引起的原子电离截面，并开发了神经网络替代模型CDWEIS-NN，以扩展数据库覆盖范围，结果与实验吻合良好。

Antiproton collisions with molecular hydrogen

Theoretical antiproton and proton cross sections for ionization and excitation of hydrogen molecules as well as energy spectra of the ionized electrons were calculated in the impact-energy range from 8 to 4000 keV. The cross sections were computed with the close-coupling formulation of the semi-classical impact-parameter method. The target was described using a one-active electron model centered on the target and assuming a fixed internuclear distance during the collision process. The dependence of the ionization cross sections on the internuclear distance is examined. The present cross sectio…

对《慢反质子在LiF中电子阻止的异常现象》的评论，arXiv:2501.14381

Comment on 'Anomalies in the Electronic Stopping of Slow Antiprotons in LiF', arXiv:2501.14381

本文评论了PRL134关于慢反质子在LiF中电子阻止的研究，通过重新审视绝热电离模型(AIM)并将其计算结果与实验数据对比，指出了PRL134结果的严重问题，并批判性地检验了其中与既定理论不符或论证不足的假设与主张。

Density functional theory investigation of antiproton-helium collisions

We revisit recent developments in the theoretical foundations of time-dependent density functional theory (TDDFT). TDDFT is then applied to the calculation of total cross sections for ionization processes in the antiproton-Helium collision system. The Kohn-Sham potential is approximated as the sum of the Hartree-exchange potential and a correlation potential that was proposed in the context of laser-induced ionization. Furthermore, some approaches to the problem of calculating the ionization probabilities from the density are discussed. Small projectile energies below 5keV are considered as we…

The atomic ionization, capture, and stopping cross sections by multicharged ions satisfy the Benford law

The applicability of the Benford law for different data sets of atomic cross sections by ion impact is studied. We find that the data sets corresponding to theoretical ionization and capture cross sections of neutral targets by multicharged ions satisfy quite well the Benford law, not only for the first digits but also within a given order of magnitude. Experimental stopping power values from the International Atomic Energy Agency database were also scrutinized, but in this case the Benford conformity was not so satisfactory due to its small rank width. In all cases, errors, densities of prime…

Complete break-up of the helium atom by proton and antiproton impact

We present a fully {\it ab initio}, non-perturbative, time-dependent approach to describe single and double ionization of helium by proton and antiproton impact. A flexible and accurate finite-element discrete-variable-representation is applied to discretize the problem on the radial grid in spherical coordinates. Good agreement with the most recent experimental data for absolute angle-integrated cross sections is obtained over a wide range of incident projectile energies between 3 keV and 6 MeV. Furthermore, angle-differential cross sections for two-electron ejection are predicted for a proto…

反质子在氦中能量损失分布中的电子关联效应

Electron correlations in the antiproton energy loss distribution in He

本文通过从头计算反质子在氦中的电子微分能量转移截面，发现电子关联效应使能量离散超过玻尔极限。

Antiproton--hydrogen collisions calculation by Coulomb wave function discrete variable method

Nonrelativistic collision of proton and antiproton with hydrogen atom described by solving time-dependent Schrodinger equation numerically. Coulomb wave function discrete variable method (CWDVR) had been used to calculate electron wave function evolution, while projectile defined classically, moving along the straight line trajectories with constant velocity. The ionization amplitude calculated by projection of the wave function into continuum wave function of the hydrogen electron. The differential cross sections calculated depending on projectile impact energy, scattering angle and electron …

基于从头算的反质子与氦相互作用研究

Interaction of antiproton with helium based on ab-initio calculations

本研究采用含时耦合通道从头算方法，结合有限基组与半经典含时库仑势，计算10、50和100 keV下反质子-氦碰撞电离截面，并观测到微分分布中的反尖点结构。

Antiproton and proton collisions with the alkali metal atoms Li, Na, and K

Single-electron ionization and excitation cross sections as well as cross sections for excitation into the first excited p state of the alkali metal atoms Li(2s), Na(3s) and K(4s) colliding with antiprotons and protons were calculated using a time-dependent channel-coupling approach. For antiprotons an impact-energy range from 0.25 to 1000 keV and for protons from 2 to 1000 keV was considered. The target atoms are treated as effective one-electron systems using a model potential. The results are compared with theoretical and experimental data from literature and calculated cross sections for a…

Multielectronic processes in particle and antiparticle collisions with rare gases

In this chapter we analyze the multiple ionization by impact of |Z|=1 projectiles: electrons, positrons, protons and antiprotons. Differences and similarities among the cross sections by these four projectiles allows us to have an insight on the physics involved. Mass and charge effects, energy thresholds, and relative importance of collisional and post-collisional processes are discussed. For this purpose, we performed a detailed theoretical-experimental comparison for single up to quintuple ionization of Ne, Ar, Kr and Xe by particles and antiparticles. We include an extensive compilation of…

反质子-氢原子相互作用中的电子发射研究：基于单中心基组生成法

Electron Emission in Antiproton-Hydrogen Interactions Studied with the One-Centre Basis Generator Method

利用单中心基组生成法研究反质子撞击氢原子在中等能量下的电子发射，通过单中心展开时间依赖的薛定谔方程，采用氢原子轨道的赝态基组，构建电子连续态的有效表示，计算离子化概率并提取能谱，得到平滑的电子发射截面。

Calculation of Energy Loss in Antiproton Collisions with Many-Electron Systems using Ehrenfest's Theorem

Energy loss in collisions of charged projectiles with many-electron systems can be dealt with in time-dependent density functional theory by invoking Ehrenfest's theorem for the time evolution of expectation values of observables. We derive an exact expression for the evaluation of energy loss for systems described in a target reference frame, which is a functional of the electron density. Using an approximation scheme we then apply the expression to antiproton-atom collisions at intermediate and high energies within the framework of the basis generator method. The calculations are performed w…

重离子等离子体阻止本领的相对论效应

Relativistic effects on stopping power of plasmas with heavy ions

本文利用介电形式理论和壳层局域等离子体近似，研究了钨等离子体中相对论效应对质子阻止本领的影响，揭示了高Z离子等离子体中束缚电子贡献的重要性，为聚变能研究提供了关键数据。

硅中核反冲电离效率：从约 50 eV 到 3 MeV

Ionization efficiency for nuclear recoils in silicon from $\sim 50$ eV to $3$ MeV

本文提出一个扩展 Lindhard 理论的硅核反冲电离效率模型，考虑原子键断裂、电子阻止、离散及屏蔽效应，覆盖约 50 eV 至 3 MeV 能量范围。

过渡金属中d电子对阻止本领的贡献

The d-electron contribution to the stopping power of transition metals

本文提出一种非微扰模型，利用原子非均匀动量分布描述过渡金属d电子对低能阻止本领的贡献，并与价电子和内壳层方法结合，实现对Ni、Pd、Pt、Cu、Ag、Au从低能到高能阻止本领的一致理论描述。

通过含时波函数直接确定全微分截面

Direct determination of the fully differential cross section by the time-dependent wave function

本文提出用含时波函数直接确定质子与反质子同氢原子碰撞电离的全微分截面，通过二维傅里叶变换得到特定散射角波函数，无需计算空间积分即可获得与传统跃迁振幅方法一致的结果。