Positron scattering and annihilation on noble-gas atoms

D. G. Green*, J. A. Ludlow, G. F. Gribakin

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

67 Citations (Scopus)
400 Downloads (Pure)

Abstract

Positron scattering and annihilation on noble-gas atoms is studied ab initio using many-body theory methods for positron energies below the positronium formation threshold. We show that in this energy range, the many-body theory yields accurate numerical results and provides a near-complete understanding of the positron–noble-gas atom system. It accounts for positron-atom and electron-positron correlations, including the polarization of the atom by the positron and the nonperturbative effect of virtual positronium formation. These correlations have a large influence on the scattering dynamics and result in a strong enhancement of the annihilation rates compared to the independent-particle mean-field description. Computed elastic scattering cross sections are found to be in good agreement with recent experimental results and Kohn variational and convergent close-coupling calculations. The calculated values of the annihilation rate parameter 𝑍eff (effective number of electrons participating in annihilation) rise steeply along the sequence of noble-gas atoms due to the increasing strength of the correlation effects, and agree well with experimental data.


Original languageEnglish
Article number032712
Number of pages19
JournalPhysical Review A
Volume90
Issue number3
DOIs
Publication statusPublished - 10 Sept 2014

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