INTERPRETATION OF POSITRON LIFETIME SPECTRA ARISING FROM MICELLAR SOLUTIONS. DETERMINATION OF THE ORTHO-POSITRONIUM DIFFUSION COEFFICIENT IN THE SOLVENT.

Sz Vass, Z. Kajcsos

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6 Citations (Scopus)

Abstract

Positron lifetime spectra arising from micellar solutions of sodium dodecylsulphate (SDS) are interpreted in terms of a classical positronium diffusion model published earlier. Unlike the generally accepted assumptions, this model results in a non-exponential ortho-positronium ( omicron -Ps) lifetime density function. A new method is presented for the simultaneous fitting of this lifetime density function to independent lifetime spectra recorded under the same experimental conditions. Among the fit parameters D//p, the diffusion coefficient of omicron -Ps in the solvent (i. e. heavy water) phase is studied in detail; a detailed error analysis for D//p is also given. Provided that the mean aggregation number of SDS micelles is about 60, the published D//p values show that the diffusion coefficient of omicron -Ps in (heavy) water at room temperature is lower than that of small ions and molecules and the Arrhenius plot indicates a strong omicron -Ps localization in the solvent. The hydrodynamic radius of omicron -Ps is calculated.

Original languageEnglish
Pages (from-to)403-416
Number of pages14
JournalRadiation Physics and Chemistry
Volume32
Issue number3
Publication statusPublished - 1988

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positronium
positrons
diffusion coefficient
life (durability)
heavy water
sodium
error analysis
micelles
plots
hydrodynamics
radii
room temperature
molecules
ions

ASJC Scopus subject areas

  • Radiation

Cite this

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title = "INTERPRETATION OF POSITRON LIFETIME SPECTRA ARISING FROM MICELLAR SOLUTIONS. DETERMINATION OF THE ORTHO-POSITRONIUM DIFFUSION COEFFICIENT IN THE SOLVENT.",
abstract = "Positron lifetime spectra arising from micellar solutions of sodium dodecylsulphate (SDS) are interpreted in terms of a classical positronium diffusion model published earlier. Unlike the generally accepted assumptions, this model results in a non-exponential ortho-positronium ( omicron -Ps) lifetime density function. A new method is presented for the simultaneous fitting of this lifetime density function to independent lifetime spectra recorded under the same experimental conditions. Among the fit parameters D//p, the diffusion coefficient of omicron -Ps in the solvent (i. e. heavy water) phase is studied in detail; a detailed error analysis for D//p is also given. Provided that the mean aggregation number of SDS micelles is about 60, the published D//p values show that the diffusion coefficient of omicron -Ps in (heavy) water at room temperature is lower than that of small ions and molecules and the Arrhenius plot indicates a strong omicron -Ps localization in the solvent. The hydrodynamic radius of omicron -Ps is calculated.",
author = "Sz Vass and Z. Kajcsos",
year = "1988",
language = "English",
volume = "32",
pages = "403--416",
journal = "Radiation Physics and Chemistry",
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AU - Vass, Sz

AU - Kajcsos, Z.

PY - 1988

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N2 - Positron lifetime spectra arising from micellar solutions of sodium dodecylsulphate (SDS) are interpreted in terms of a classical positronium diffusion model published earlier. Unlike the generally accepted assumptions, this model results in a non-exponential ortho-positronium ( omicron -Ps) lifetime density function. A new method is presented for the simultaneous fitting of this lifetime density function to independent lifetime spectra recorded under the same experimental conditions. Among the fit parameters D//p, the diffusion coefficient of omicron -Ps in the solvent (i. e. heavy water) phase is studied in detail; a detailed error analysis for D//p is also given. Provided that the mean aggregation number of SDS micelles is about 60, the published D//p values show that the diffusion coefficient of omicron -Ps in (heavy) water at room temperature is lower than that of small ions and molecules and the Arrhenius plot indicates a strong omicron -Ps localization in the solvent. The hydrodynamic radius of omicron -Ps is calculated.

AB - Positron lifetime spectra arising from micellar solutions of sodium dodecylsulphate (SDS) are interpreted in terms of a classical positronium diffusion model published earlier. Unlike the generally accepted assumptions, this model results in a non-exponential ortho-positronium ( omicron -Ps) lifetime density function. A new method is presented for the simultaneous fitting of this lifetime density function to independent lifetime spectra recorded under the same experimental conditions. Among the fit parameters D//p, the diffusion coefficient of omicron -Ps in the solvent (i. e. heavy water) phase is studied in detail; a detailed error analysis for D//p is also given. Provided that the mean aggregation number of SDS micelles is about 60, the published D//p values show that the diffusion coefficient of omicron -Ps in (heavy) water at room temperature is lower than that of small ions and molecules and the Arrhenius plot indicates a strong omicron -Ps localization in the solvent. The hydrodynamic radius of omicron -Ps is calculated.

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