Positronium formation in the bimary molecular solid solutions Tb 1Àx Eu x (dpm) 3 (dpm = dipivaloylmethanate) has been investigated. A strong linear correlation between the 5 D 4 Tb(III) energy level excited state lifetime and the positronium formation probability has been observed. This correlation indicates that the ligand-to-metal charge transfer LMCT states act in both luminescence quenching and positronium formation inhibition, as previously proposed. A kinetic mechanism is proposed to explain this correlation and shows that excited electronic states have a very important role in the positronium formation mechanism.
Positronium formation in the bimary molecular solid solutions Tb 1Àx Eu x (dpm) 3 (dpm = dipivaloylmethanate) has been investigated. A strong linear correlation between the 5 D 4 Tb(III) energy level excited state lifetime and the positronium formation probability has been observed. This correlation indicates that the ligand-to-metal charge transfer LMCT states act in both luminescence quenching and positronium formation inhibition, as previously proposed. A kinetic mechanism is proposed to explain this correlation and shows that excited electronic states have a very important role in the positronium formation mechanism.
a b s t r a c tPositronium formation was investigated in benzene and naphthalene compounds with electron donating (ANH 2 and AOH) and electron withdrawing (ACN and ANO 2 ) substituents. The results exhibit an increase in the positronium formation yield whenever donating groups are bound to the ring and a decrease with withdrawing groups. These results can be attributed to the p-system electronic density variation in the aromatic ring. The amount of positronium obtained, I 3 parameter, has been correlated with the Hammett (r) and Brown-Okamoto (r þ p ) constants and adjusted through the modified Hammett equation, which employs the ratio I 3 /I / 3 , yielding a satisfactory fit.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.