NUKLEONIKA 2013, 58(1):235-240

 


ORTHO-POSITRONIUM MIGRATION IN MESOPORES
OF MCM-41, MSF AND SBA-3



Radosław Zaleski1, Artur Błażewicz1, Agnieszka Kierys2

1 Maria Curie-Skłodowska University, Institute of Physics,
Department of Nuclear Methods,
1 M. Curie-Skłodowskiej Sq., 20-031 Lublin, Poland

2 Maria Curie-Skłodowska University, Faculty of Chemistry,
Department of Adsorption,
3 M. Curie-Skłodowskiej Sq., 20-031 Lublin, Poland



Three materials: MCM-41, MSF and SBA-3 with a very similar pore diameter but different lengths of cylindrical pores were investigated using the nitrogen sorption method and positron annihilation lifetime spectroscopy. The size of primary pores and interparticle spaces obtained by both methods is similar. However, volume ratios between the discussed kinds of pores found by the above-mentioned methods differ significantly. Such discrepancy is the result of both ortho-positronium migration and the inaccessibility of the pores for nitrogen. Comparing the results of nitrogen sorption and positron annihilation lifetime spectroscopy allows us to estimate that connectivity between the primary pores and the interparticle spaces is the highest in MCM-41 and lowest in SBA-3.


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