Multiple ionization processes involving fast charged particles

Popov, Yu. V.; Чулуунбаатар, О.; Shablov, V. L.; Kouzakov, Konstantin

doi:10.1134/s1063779610040040

Cited by 6 publications

(5 citation statements)

References 88 publications

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“…with the coefficients a i and b i for Ne, Ar, Kr and Xe being included in table 1. Note that in (8) we consider the potential created by the positive ion (the nucleus and the passive electrons), the active electron has already been considered in the ionization calculation.…”

Section: The Charge Effectmentioning

confidence: 99%

“…MI processes arising in electron-atom and ion-atom collisions [8] play an important role both in the basic understanding of the many-electron problem in atomic physics (multiple-electron transitions, electron correlation effects, collisional and post-collisional electron emission) and in different applications such as charge-state distributions of ions in plasmas and other environments with an abundance of energetic electrons.…”

Section: Introductionmentioning

confidence: 99%

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Electron-impact multiple ionization of Ne, Ar, Kr and Xe

Montanari

Miraglia

2014

J. Phys. B: At. Mol. Opt. Phys.

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This work describes the multiple ionization cross sections of rare gases by electron-impact. We pay special attention to the high energy region (0.1-10 keV) where the direct ionization is a minor contribution and the post-collisional electron emission dominates the final target charge state. We report here electron-impact single to sextuple ionization cross sections and total ionization cross sections including direct and post-collisional processes, even in the total values. We use the continuum distorted wave and the first Born approximations adapted to describe light-particle impact, i.e. energy, mass and trajectory corrections are incorporated, the latter by considering the electron-target potential and by using the Abel transformation. Auger-type post-collisional contributions are included in the multinomial expansion through experimental branching ratios after single ionization events. Tabulations of these experimental branching ratios for all the orbitals of the four targets are included. Present results are compared with the large amount of electron-impact experimental data available. We have obtained a good description of the multiple-ionization measurements at high energies, where the post-collisional ionization dominates. At intermediate energies, our theoretical results show the correct tendency, with the electron-impact ionization cross sections being far below the proton-impact ones.

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Section: The Charge Effectmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Electron-impact multiple ionization of Ne, Ar, Kr and Xe

Montanari

Miraglia

2014

J. Phys. B: At. Mol. Opt. Phys.

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“…MDCS data, for the experimental geometries providing information about dynamics of the ionization process, were collected for (e,2e) on atoms [4][5][6][7][8][9], diatomic [10][11][12][13][14][15] and polyatomic molecules [14,16] for the cases of fast [4,10,11], intermediate [7][8][9][13][14][15][16] and low-energy incident electrons [5][6][7]12]. For the interpretation of these results, theorists used both perturbative methods, based on the approximate wave functions of electron continuum (see [17] and references therein), and ab-initio methods, such as convergent close coupling (CCC) [18], time-dependent close coupling (TDCC) [19], external complex scaling (ECS) [20], and R-matrix with pseudostates (RMPS) [21]. Ionization of diatomic molecules is a subject of special interest for both theorists and experimentalists, because this is a natural model for demonstration of Young-type double-slit interference [11].…”

Section: Introductionmentioning

confidence: 99%

Calculation of intermediate-energy electron-impact ionization of molecular hydrogen and nitrogen using the paraxial approximation

Serov

2011

Phys. Rev. A

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We have implemented the paraxial approximation followed by the time-dependent Hartree-Fock method with frozen core for the single impact ionization of atoms and two-atomic molecules.It reduces the original scattering problem to the solution of a five-dimensional time-dependent Schrödinger equation. Using this method we calculated the multi-fold differential cross section of the impact single ionization of the helium atom, the hydrogen molecule and the nitrogen molecule by the impact of an intermediate-energy electrons. Our results for the He and the H 2 are quite close to the experimental data. Surprisingly, for N 2 the agreement is good for the paraxial approximation combined with first Born approximation, but worse for pure paraxial approximation, apparently because of the insufficiency of the frozen core approximation.

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“…At first glance, multiple ionization should be described by successive ionizations of bound electrons (the so-called ladder process, or independent ionization process); however, this is not the case. The comparison of calculations based on the model of the ladder process for the n-electron ionization total cross section [1] with experimental results [2] shows that the simple first Born approximation (Bethe formula [3]) seems sufficient * bachau@celia.u-bordeaux1.fr † popov@srd.sinp.msu.ru ‡ bernard.piraux@uclouvain.be to describe multiple electron release [1]. Yet the mechanism of 2,3,4, .…”

Section: Introductionmentioning

confidence: 99%

Two-photon double ionization of atoms in attosecond x-ray radiation fields

et al. 2010

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We consider two-photon double ionization of helium with 100, 200, and 400 eV excess energy for the two ejected electrons, corresponding to photon energies of 89.5, 139.5, and 239.5 eV, respectively. We focus on the case of ultrashort pulses (two oscillations of the field) and develop an approach to calculate the two-photon transition matrix elements within the lowest order of the time-dependent perturbation theory. One of the major difficulties in calculating such amplitudes is the infinite summation over a complete set of intermediate states.In the subfemtosecond regime, however, this summation can be performed accurately by means of the closure approximation. This results in a simple expression for the two-photon amplitude that contains a dipole term and a quadrupole term. The dipole term can be clearly associated to a process in which each electron absorbs a photon whereas the quadrupole term is associated to a process in which one electron absorbs two photons and ejects the second one by collision. We analyze in detail how the relative weight of both processes influences the behavior of the electron energy and angular distributions. In particular we study how the shape of these distributions changes with the amount of electron correlations taken into account in both initial and final states. For 100 eV excess energy, our results for the electron energy distribution are compared with those obtained by solving the time-dependent Schrödinger equation. All these results unveil the crucial role of electron correlations in this transient regime of ionization which is neither sequential nor direct.

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Multiple ionization processes involving fast charged particles

Cited by 6 publications

References 88 publications

Electron-impact multiple ionization of Ne, Ar, Kr and Xe

Electron-impact multiple ionization of Ne, Ar, Kr and Xe

Calculation of intermediate-energy electron-impact ionization of molecular hydrogen and nitrogen using the paraxial approximation

Two-photon double ionization of atoms in attosecond x-ray radiation fields

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