Positron annihilation and positronium trapping in zeolites

Zs Kajcsos, G. Duplâtre, L. Liszkay, L. Lohonyai, L. Varga, K. Lázár, G. Pál-Borbély, H. K. Beyer, J. L. Paillaud

Research output: Contribution to journalConference article

6 Citations (Scopus)

Abstract

Positron annihilation (PA) studies in zeolites show the coexistence of several annihilation channels. Up to seven lifetimes, from 0.13 ns to 142 ns, with intensities of the long-lived components reaching 30 %, can be resolved, their number and significance being limited by statistical accuracy and ill-defined data fitting. The longest lifetimes denote low interaction of orthopositronium, o-Ps, with its surroundings. PA parameters from positron lifetime or Doppler spectroscopy applied to zeolite samples (whether substituted or not) depend on the preparation mode, the presence of adsorbed gases, water, impurities, etc. A good agreement for the long-lived components, ascribed to trapped o-Ps states localized in various extra and intra-structural open sites, is obtained through the Eldrup model. Correct characterization of these components requires corrections for the 3γ/2γ counting efficiency ratio. It is concluded that o-Ps trapping poses a limitation to the applicability of PA to structural investigation in porous systems.

Original languageEnglish
Pages (from-to)239-243
Number of pages5
JournalMaterials Science Forum
Volume445-446
Publication statusPublished - Jul 27 2004
EventPositron Annihilation: Proceedings of the 13th International Conference on Positron Annihilation, ICPA-13 - Kyoto, Japan
Duration: Sep 7 2003Sep 12 2003

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Keywords

  • 3γ/2γ
  • Detection
  • Porous Solids
  • Positron Lifetime Fitting
  • Trapped o-Ps
  • Zeolites

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

Cite this

Kajcsos, Z., Duplâtre, G., Liszkay, L., Lohonyai, L., Varga, L., Lázár, K., Pál-Borbély, G., Beyer, H. K., & Paillaud, J. L. (2004). Positron annihilation and positronium trapping in zeolites. Materials Science Forum, 445-446, 239-243.