CAPILLARY CONDENSATION IN POROUS ALUMINA OBSERVED BY POSITRONIUM LIFE TIME SPECTROSCOPY (PRELIMINARY RESULTS)
Pages 5-8
Eugeniu Ivanov, Ion Vata, Stefan Toderian,Dorin Dudu, Ion Rusen, Nitisor Stefan
Abstract
Positronium annihilation life time spectroscopy (PALS) has been used to study capillary condensation of different gases adsorbed in mesoporous alumina powder. The isotherms exhibit features which are associated with a shifted gas-liquid transition. The isotherm data suggest that pore filling occurs via progressive layer formation at the pore surface followed by an abrupt gas-liquid phase transition at some pressure below the bulk saturated vapour pressure.