Electron shell contributions to gamma-ray spectra of positron annihilation in noble gases

F. Wang, L. Selvam, G. F. Gribakin, C.M. Surko

Research output: Contribution to journalArticlepeer-review

16 Citations (Scopus)


Gamma-ray positron annihilation spectra of the noble gases are simulated using computational chemistry tools for the bound electron wavefunctions and plane-wave approximation for the low-energy positron. The present annihilation line shapes, i.e. the full width at half maximum, Delta epsilon, of the gamma-ray annihilation spectra for He and Ar (valence) agree well with available independent atomic calculations using a different algorithm. For other noble gases they achieve moderate agreement with the experimental measurements. It is found that the contributions of various atomic electron shells to the spectra depend significantly on their principal quantum number n and orbital angular momentum quantum number l. The present study further reveals that the outermost ns electrons of the noble gases exhibit spectral line shapes in close agreement with those measured, indicating (as expected) that the measurements are not due to a simple sum over the momentum densities for all atomic electrons. The robust nature of the present approach makes it possible for us to proceed to more complex molecular systems using the tools of modern computational chemistry.
Original languageEnglish
Article number165207
Pages (from-to)165207
Number of pages1
JournalJournal of Physics B: Atomic Molecular and Optical Physics
Issue number16
Publication statusPublished - 28 Aug 2010

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Atomic and Molecular Physics, and Optics


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