Oliveira F.C.,Laboratorio Of Espectroscopia Of Aniquilaao Of Positrons Leap |
Oliveira F.C.,Federal University of Minas Gerais |
Oliveira A.M.,Federal University of Minas Gerais |
Donnici C.L.,Laboratorio Of Espectroscopia Of Aniquilaao Of Positrons Leap |
And 5 more authors.
Chemical Physics Letters | Year: 2011
Positronium formation was investigated in benzene and naphthalene compounds with electron donating (NH2 and OH) and electron withdrawing (CN and NO2) 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 π-system electronic density variation in the aromatic ring. The amount of positronium obtained, I3 parameter, has been correlated with the Hammett (σ) and Brown-Okamoto (σp+) constants and adjusted through the modified Hammett equation, which employs the ratio I3/I3φ, yielding a satisfactory fit. © 2011 Elsevier B.V. All rights reserved.