Perspectives on Physics with Low Energy Positrons: Fundamentals, Beams and Scattering

Charlton, M.

doi:10.1007/0-306-47613-4_13

Cited by 2 publications

(5 citation statements)

References 28 publications

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“…As a result, the positron does not penetrate far inside the atom. When the positron is outside the atom, it polarizes the electron cloud, giving rise to a long-range, attractive polarization potential, V(r) = −α d e 2 /2r 4 , where α d is the dipole polarizability of the atom. This asymptotic form is identical for electrons and positrons.…”

Section: Atomsmentioning

confidence: 99%

“…This enhancement can be viewed as arising from the existence of a virtual level for the projectile, at an energy given by ε = h2 /(2ma 2 ) = 1/2a 2 . 4 These virtual levels also lead to enhanced positron annihilation cross sections [29,52,56].…”

Section: Atomsmentioning

confidence: 99%

“…The use of high-resolution trap-based positron beams for scattering and annihilation experiments is discussed, as well as theoretical advances, such as predicting positron binding to neutral species and the understanding of the effects of virtual positron states and resonances. The reader is referred to previous review material for a discussion of earlier work and aspects of the field not covered here [1][2][3][4][5].…”

Section: Introductionmentioning

confidence: 99%

“…There are areas of positron atomic physics not covered in this review. For example, experiments in atmospheric and higher pressure gases show evidence of density-dependent effects, indicative of positron interactions with several atoms or molecules [4,48]. Another important area is positronium scattering from atomic and molecular targets [5,49].…”

Section: Introductionmentioning

confidence: 99%

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Low-energy positron interactions with atoms and molecules

Surko

Gribakin

Buckman

2005

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

275

242

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This paper is a review of low-energy positron interactions with atoms and molecules. Processes of interest include elastic scattering, electronic and vibrational excitation, ionization, positronium formation and annihilation. An overview is presented of the currently available theoretical and experimental techniques to study these phenomena, including the use of trap-based positron beam sources to study collision processes with improved energy resolution. State-resolved measurements of electronic and vibrational excitation cross sections and measurement of annihilation rates in atoms and molecules as a function of incident positron energy are discussed. Where data are available, comparisons are made with analogous electron scattering cross sections. Resonance phenomena, common in electron scattering, appear to be less common in positron scattering. Possible exceptions include the sharp onsets of positron-impact electronic and vibrational excitation of selected molecules. Recent energy-resolved studies of positron annihilation in hydrocarbons containing more than a few carbon atoms provide direct evidence that vibrational Feshbach resonances underpin the anomalously large annihilation rates observed for many polyatomic species. We discuss open questions regarding this process in larger molecules, as well as positron annihilation in smaller molecules where the theoretical picture is less clear.

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Section: Atomsmentioning

confidence: 99%

Section: Atomsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Low-energy positron interactions with atoms and molecules

Surko

Gribakin

Buckman

2005

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

275

242

View full text Add to dashboard Cite

show abstract

“…The main difference between that experiment and a temperature study using the traditional lifetime method would be that in the latter both the positron and gas temperature would be changed. Theoretical guidance on the potential utility of such studies would be of value, as would a comprehensive investigation of annihilation for simple molecules for which Z eff Z [23,24]. Such challenging studies will hopefully be undertaken in the not-too-distant future [24].…”

mentioning

confidence: 99%