<abstract xmlns="http://www.w3.org/1999/xhtml">The <italic>o</italic>-Ps mean lifetime value in liquids decreases in the presence of the paramagnetic oxygen molecules via the <italic>ortho-para</italic> conversion process. This effect was observed for several organic samples composed of carbon and hydrogen atoms differing in the arrangement of atoms forming the molecule, e.g. <italic>n</italic>-alkanes, alcohols, branched isomer of alkane, cycloalkane. The usually observed tendency of the <italic>o</italic>-Ps lifetime value to be an increasing function of temperature (in the case of measurements performed in vacuum) changes to a decreasing one in the presence of O2 dissolved in the sample. The difference between the <italic>o</italic>-Ps lifetimes measured in samples in vacuum and in the presence of O2 increases with the distance from the melting point. The <italic>ortho-para</italic> constant rate λconv was estimated to be ~130 μs−1 at 300 K for three compounds investigated.</abstract>

The o-Ps mean lifetime value in liquids decreases in the presence of the paramagnetic oxygen molecules via the ortho-para conversion process. This effect was observed for several organic samples composed of carbon and hydrogen atoms differing in the arrangement of atoms forming the molecule, e.g. n-alkanes, alcohols, branched isomer of alkane, cycloalkane. The usually observed tendency of the o-Ps lifetime value to be an increasing function of temperature (in the case of measurements performed in vacuum) changes to a decreasing one in the presence of O2 dissolved in the sample. The difference between the o-Ps lifetimes measured in samples in vacuum and in the presence of O2 increases with the distance from the melting point. The ortho-para constant rate λconv was estimated to be ~130 μs−1 at 300 K for three compounds investigated.

<italic>Ortho-para</italic> spin conversion of Ps by paramagnetic O2 dissolved in organic compounds

Department of Nuclear Methods, Institute of Physics, Maria Curie-Sklodowska University, 1 M. Curie-Sklodowskiej Sq., 20-031 Lublin, Poland, Tel.: +48 81 537 6286, Fax: +48 81 537 6191

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 spin conversion of Ps by paramagnetic O dissolved in organic compounds

The o-Ps mean lifetime value in liquids decreases in the presence of the paramagnetic oxygen molecules via the ortho-para conversion process. This effect was...

Ortho-para spin conversion of Ps by paramagnetic O₂ dissolved in organic compounds

Publié en ligne: 01 déc. 2015

Pages: 801 - 804

Reçu: 01 juil. 2015

Accepté: 18 août 2015

DOI: https://doi.org/10.1515/nuka-2015-0144

Mots clés
alcohols, cyclohexane, isooctane, -alkanes, conversion, paramagnetic molecule

© 2015 Bożena Zgardzińska et al., published by De Gruyter Open

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Ortho-para spin conversion of Ps by paramagnetic O2 dissolved in organic compounds

Publié en ligne: 01 déc. 2015

Pages: 801 - 804

Reçu: 01 juil. 2015

Accepté: 18 août 2015

DOI: https://doi.org/10.1515/nuka-2015-0144

Mots clésalcohols, cyclohexane, isooctane, -alkanes, conversion, paramagnetic molecule

© 2015 Bożena Zgardzińska et al., published by De Gruyter Open

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Ortho-para spin conversion of Ps by paramagnetic O₂ dissolved in organic compounds

Mots clés
alcohols, cyclohexane, isooctane, -alkanes, conversion, paramagnetic molecule