Antiproton-impact ionization of H, He and Li

Pindzola, M. S.; Lee, T G; Colgan, J.

doi:10.1088/0953-4075/44/20/205204

Cited by 18 publications

(10 citation statements)

References 23 publications

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“…Within the framework of such a close-coupling scheme, a number of works assumed a static correlation of the outer electron with the inner one confined to the 1s orbital, i.e., the frozen-core approximation. More sophisticated calculations by Igarashi et al [15], Pindzola et al [21], and Foster et al [22], which allowed for multiple configurations for both target electrons, produced total ionization cross sections that differed considerably from the values obtained in the frozen-core approximation. However, in these calculations the type of basis functions used to diagonalize the target Hamiltonian does not allow for inclusion of double-continuum states in the description of the He structure, since one would run into the problem of mixing single-and double-ionization channels.…”

Section: Introductionmentioning

confidence: 96%

“…Earlier works [13,14] based on perturbative methods produced reasonable results for several integrated cross sections representing single electron processes at high impact energies. More sophisticated approaches [4,5,[15][16][17][18][19][20][21][22][23][24] are based on the semiclassical close-coupling formalism, in which the antiproton motion is treated classically by means of straight-line trajectories. This approximation is well accepted in ion-atom collisions.…”

Section: Introductionmentioning

confidence: 99%

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Wave-packet continuum-discretization approach to single ionization of helium by antiprotons and energetic protons

et al. 2017

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The recently developed wavepacket continuum-discretization approach [Phys. Rev. A 94, 022703 (2016)] is extended to antiproton-helium collisions. The helium target is treated as a three-body Coulomb system using a frozen-core approximation, in which the electron-electron correlation within the target is accounted for through the static interaction. The Schrödinger equation for the helium target is solved numerically to yield bound and continuum states of the active electron. The resulting continuum state is used to construct wavepacket pseudostates with arbitrary energies. The energies of the pseudostates are chosen in a way that is ideal for detailed differential ionization studies. Twoelectron target wave functions, formed from the bound and continuum wavepacket states of the active electron and the 1s orbital of He + , are then utilized in the single-center semiclassical impactparameter close-coupling scheme. A comprehensive set of benchmark results, from angle-integrated to fully differential cross sections for antiproton-impact single ionization of helium in the energy range from 1 keV to 1 MeV is provided. Furthermore, we use our single-center convergent closecoupling approach to study fully differential single ionization of helium by 1 MeV proton impact. The calculated results are in good agreement with recent experimental measurements by Gassert et al. [Phys. Rev. Lett. 116, 073201 (2016)] for all considered geometries.

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Section: Introductionmentioning

confidence: 96%

Section: Introductionmentioning

confidence: 99%

Wave-packet continuum-discretization approach to single ionization of helium by antiprotons and energetic protons

et al. 2017

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“…From the theoretical point of view, multiple ionization is a complex many-electron process to describe. In the case of ionization of He, sophisticated calculations have been developed that include correlation among electrons (the theoretical work on helium target is very extensive; see for example [26][27][28][29][30][31][32] and [15] and references therein). However, the extension to other targets is far from the present possibilities.…”

Section: Introductionmentioning

confidence: 99%

Antiproton, proton and electron impact multiple ionization of rare gases

Montanari¹,

Miraglia²

2012

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

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We present a study on multiple ionization of Ne, Ar, Kr and Xe by antiproton, proton and electron impact. Four different aspects are involved in this work. First, the theoretical calculations of ionization probabilities by impact of antiprotons and protons, in an extended energy region (25 keV to 10 MeV), using the continuum distorted-wave eikonal initial state approximation and the first Born approximation. Second, the inclusion of Auger-type post-collisional contributions through experimental photoionization branching ratios. These contributions to multiple ionization are very important in the high-energy region. Third, the comparison with the available experimental data on multiple ionization by protons and antiprotons in the extended energy range, and by electrons for high-impact velocities, where proton, antiproton and electron impact results are expected to converge. It is also the energy region where direct ionization does not explain the experimental results, and the post-collisional ionization is the main contribution to multiple ionization. And fourth, total ionization cross sections are calculated and compared with the antiproton, proton and electron experimental data, showing the importance of Auger-type multiple ionization for heavy targets even at the level of total cross sections. Gross and count cross sections are scrutinized.

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“…On one hand, the TDCC method based on an expansion of a one-electron threedimensional wave function was used in single ionization processes in single electron systems, namely H [2] and H + 2 [3], and in the single active electron approximation in He [2], Li [2] and H 2 [4]. On the other hand, the TDCC method based on an expansion of a two-electron sixdimensional wave function was applied to single and double ionization ionization processes in He [2,[5][6][7][8][9] and H 2 [3,4,10]. The TDCC method based on an expansion of a two-electron six-dimensional wave function scheme represents a challenge from a computational viewpoint and massive parallel computers are employed to obtain the theoretical quantities needed to compare with the experimental measurements.…”

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confidence: 99%

Fully differential cross section for O8+-impact ionization of Li

2013

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We present various differential cross sections for the single ionization of Li by O 8+ ions. We use a time-dependent close-coupling approach to model the evolution of a one-active-electron wavefunction in the field of the incoming projectile for a range of impact parameters. In addition a Fourier transform approach is used to extract differential cross sections for a specific projectile momentum transfer value. This scheme allows us to incorporate information about the interaction of the two heavy nuclei (the so-called NN interaction) and to assess its influence in the differential cross sections. We find noticeable differences in the shape of the differential cross sections when we include (neglect) the NN interaction. Our single differential cross section calculation shows excellent agreement with experimental data. In addition recent measured double differential cross sections as a function of electron energy and transverse momentum transfer are reasonably well reproduced by our theoretical calculations.

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Antiproton-impact ionization of H, He and Li

Cited by 18 publications

References 23 publications

Wave-packet continuum-discretization approach to single ionization of helium by antiprotons and energetic protons

Wave-packet continuum-discretization approach to single ionization of helium by antiprotons and energetic protons

Antiproton, proton and electron impact multiple ionization of rare gases

Fully differential cross section for O8+-impact ionization of Li

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