Double ionization of helium by protons and antiprotons in the energy range 0.30 to 40 MeV

Reading, J. F.; Ford, A L

doi:10.1103/physrevlett.58.543

Cited by 150 publications

(54 citation statements)

References 19 publications

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“…4 • \ p~ake PM tMo) = 0.2%, (Pd) = 0.1%, and p~ake(La) = 0.03%. These values, which slightly increase the theoretical ionization probability per M-shell electron given above, can be regarded as maximum values, since in a high-energy ion-atom collision the ejected electron moves rather slowly away from the atom and the shake-off limit is not applicable [60].…”

Section: Other Ionizing Processes and Electron Correlationmentioning

confidence: 98%

Inner-shell ionization in near-central collisions of 6.7 MeV/amu4He ions with mid-Z atoms

Carlen

Dousse

Gasser

et al. 1992

Z Phys D - Atoms, Molecules and Clusters

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Abstract. The K[3 spectra of molybdenum, palladium and lanthanum bombarded by 6.7 MeV/amu 4He ions were measured with a transmission curved crystal spectrometer. L and M satellite lines were observed and resolved. Experimental energies are compared with those calculated with a MCDF program. M-shell ionization probabilities are deduced from the measured satellite intensity ratios and compared with theoretical (SCA) predictions.The experimental values are found to be higher than the calculated ones (by a factor of 2 for La and a factor of about 4 for Mo and Pd). The influence of coupling effects, electron wave functions, electron capture, electron correlation and target activation is discussed.

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Section: Other Ionizing Processes and Electron Correlationmentioning

confidence: 98%

Inner-shell ionization in near-central collisions of 6.7 MeV/amu4He ions with mid-Z atoms

Carlen

Dousse

Gasser

et al. 1992

Z Phys D - Atoms, Molecules and Clusters

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show abstract

“…In order to describe correlation they have to solve a large set of coupled equations. Their ®rst results [13] were only in qualitative agreement with the experiment, but later Ford and Reading have performed the calculations with an enlarged basis set, obtaining very good agreement with the experimental data [14] above 300 keV/amu projectile energy. Recently, the same group has proved, that using more time intervals, and taking into account the electron correlations several times during the collision, they can obtain good results for lower projectile energies, too [15].…”

Section: Introductionmentioning

confidence: 89%

“…The most elaborated and successful theoretical description of the double ionization is that of Reading and Ford [13]. Their forced impulse Nuclear Instruments and Methods in Physics Research B 154 (1999) 123±130 www.elsevier.nl/locate/nimb method divides the collision time into sequential short segments such that an impulse approximation is forced to be valid.…”

Section: Introductionmentioning

confidence: 99%

Multi-electron processes in atomic collisions – theory

Nagy

1999

Nuclear Instruments and Methods in Physics Research Section B:

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For the theoretical description of the multi-electron processes induced by charged particle impact we use a relatively simple perturbative method. The second-order approximation is valid for protons and antiprotons of moderate and high velocities. Electron correlation is taken into account by the use of con®guration-interaction wavefunctions. The agreement with the available experimental data for some two-electron processes in the helium depends on the quality of the wavefunctions used. Ó

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“…For example, the observed differences in the double ionization have been attributed to different ionization probabilities, depending on the sign of the projectile charge, at small impact parameters [14,15]; to the Z 3 term, in accordance with the interference model of McGuire [16]; to the two electrons being removed in uncorrelated events at different internuclear distances [17,18]; and to electron correlation in the initial and final states [1,19,20]. In general, all of these models yielded reasonable agreement at high energies, but overestimated the cross sections at lower energies.…”

Section: Introductionmentioning

confidence: 99%

Empirical formulas for direct double ionization by bare ions:Z=−1to 92

2014

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Experimental cross sections and cross-section ratios reported in the literature for direct double ionization of the outer shells of helium, neon, and argon atoms resulting from bare ions ranging from protons to uranium and for antiprotons are analyzed in terms of a first-and second-order interference model originally proposed by McGuire [J. H. McGuire, Phys. Rev. Lett. 49, 1153(1982]. Empirical formulas for the various contributions to double ionization plus information about the phase difference between the first-and second-order mechanisms are extracted from the data. Projectile and target scalings are also extracted. Total cross sections and their ratios determined using these formulas and scalings are shown to be in very good agreement with experimental data for lower-Z projectiles and impact velocities larger than 1 a.u. For very-high-Z projectiles, the amount of double ionization is overestimated, probably due to saturation of probabilities that is not accounted for in scaling formulas.

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Double ionization of helium by protons and antiprotons in the energy range 0.30 to 40 MeV

Cited by 150 publications

References 19 publications

Inner-shell ionization in near-central collisions of 6.7 MeV/amu4He ions with mid-Z atoms

Inner-shell ionization in near-central collisions of 6.7 MeV/amu4He ions with mid-Z atoms

Multi-electron processes in atomic collisions – theory

Empirical formulas for direct double ionization by bare ions:Z=−1to 92

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