Electron-like and resonant scattering of positronium

Brawley, S. J.; Williams, AE; Shipman, Michael; Laricchia, G.

doi:10.1088/1742-6596/388/1/012018

Cited by 11 publications

(19 citation statements)

References 27 publications

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“…A recent experimental paper [4] confirmed earlier predictions [3] of the resonant Ps−N 2 scattering and extended previous measurements towards the challenging region of low Ps energies. In interpreting their results, the authors [4] assumed that the electron, on the average, is closer to the target than the positron [20], and averaged the electron scattering cross section for N 2 over the momentum distribution of electron in Ps.…”

Section: Introductionsupporting

confidence: 77%

“…The observed similarity between electron and Ps scattering by neutral targets [1][2][3] was recently extended to resonant scattering in Ps-N 2 [3,4] and Ps-CO 2 [2] collisions. In particular the very well-known resonance in e−N 2 scattering of the Π g symmetry [5] looks very similar to the observed resonance in the Ps-N 2 scattering if cross sections for both processes are plotted as functions of the projectile velocity.…”

Section: Introductionmentioning

confidence: 89%

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Positronium collisions with molecular nitrogen

Wilde

Fabrikant

2018

Phys. Rev. A

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For many atomic and molecular targets positronium (Ps) scattering looks very similar to electron scattering if total scattering cross sections are plotted as functions of the projectile velocity. Recently this similarity was observed for the resonant scattering by the N 2 molecule. For correct treatment of Ps-molecule scattering incorporation of the exchange interaction and short-range correlations is of paramount importance. In the present work we have used a free-electron-gas model to describe these interactions in collisions of Ps with the N 2 molecule. The results agree reasonably well with the experiment, but the position of the resonance is somewhat shifted towards lower energies, probably due to the fixed-nuclei approximation employed in the calculations. The partial-wave analysis of the resonant peak shows that its composition is more complex than in the case of e−N 2 scattering.

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Section: Introductionsupporting

confidence: 77%

Section: Introductionmentioning

confidence: 89%

Positronium collisions with molecular nitrogen

Wilde

Fabrikant

2018

Phys. Rev. A

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“…Moreover, at energies above the Ps ionization threshold (6.8 eV) the exchange interaction becomes dominant. This, to a large extent, explains the recently discovered similarity [1][2][3] between e − and Ps cross sections at intermediate energies when the cross section is plotted as a function of the projectile velocity. This similarity can also be explained, in a more direct way, within the framework of the impulse approximation [4].…”

Section: Introductionmentioning

confidence: 61%

Positronium collisions with molecular hydrogen

Wilde

Fabrikant

2015

Phys. Rev. A

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Positronium (Ps) collisions with molecular hydrogen are investigated theoretically. Elastic and Ps ionization cross sections are calculated. For elastic scattering the pseudopotential method, previously developed for rare-gas atoms, is applied. Ps ionization cross sections are calculated using the binary-encounter approximation. The results agree with swarm measurements at low collision energies and with beam measurements at higher energies. The total Ps-H 2 cross section when plotted as a function of collision velocity is close to the e −-H 2 cross section at velocities above the Ps ionization threshold confirming earlier observations [S. J. Brawley et al., Science 330, 789 (2010)]. However, below the threshold the two sets of cross sections are different because of the different nature of the long-range interaction between the projectile and the target, the polarization interaction in the case of e −-H 2 collisions and the van der Waals interaction in the case of Ps-H 2 collisions.

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“…7 looks very satisfactory. Experimental data for Ps collisions with Ar, Kr, and Xe atoms [3] do not indicate a second maximum or plateau in the total cross section as a function of Ps velocity. However, the measurements do not go above v = 2 a.u., i.e., they perhaps have not reached the regime where the ionization cross section dominates the total.…”

Section: The Electron and Positron Scattering Amplitudesmentioning

confidence: 78%

“…Note, however, that recent measurements below the Ps ionization threshold [10] indicate that the cross section continues to decrease towards lower velocities, in contrast with our prediction of a maximum in this energy region. To analyze the similarity between e − -Xe and Ps-Xe scattering, we also present the e − -Xe total [18] and measurements [19]; solid squares, measured Ps-Xe total cross section [3].…”

Section: Ps-xe Collisions and A Summary For The Heavier Rare-gas mentioning

confidence: 99%

Positronium collisions with rare-gas atoms

Gribakin¹,

Swann²,

Wilde³

et al. 2016

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

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Abstract. We calculate elastic scattering of positronium (Ps) by the Xe atom using the recently developed pseudopotential method Phys. Rev. A 90 052717] and review general features of Ps scattering from heavier rare-gas atoms: Ar, Kr and Xe. The total scattering cross section is dominated by two contributions: elastic scattering and Ps ionization (break-up). To calculate the Ps ionization cross sections we use the binary-encounter method for Ps collisions with an atomic target. Our results for the ionization cross section agree well with previous calculations carried out in the impulse approximation. Our total Ps-Xe cross section, when plotted as a function of the projectile velocity, exhibits similarity with the electron-Xe cross section for the collision velocities higher than 0.8 a.u., and agrees very well with the measurements at Ps velocities above 0.5 a.u.

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Electron-like and resonant scattering of positronium

Cited by 11 publications

References 27 publications

Positronium collisions with molecular nitrogen

Positronium collisions with molecular nitrogen

Positronium collisions with molecular hydrogen

Positronium collisions with rare-gas atoms

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