
Evidence of the participation of electronic excited states in the mechanism of positronium formation in substitutional Tb1−xEux(dpm)3 solid solutions studied by optical and positron annihilation spectroscopies
2012; Royal Society of Chemistry; Volume: 14; Issue: 28 Linguagem: Inglês
10.1039/c2cp40664k
ISSN1463-9084
AutoresFernando Fulgêncio, Fernando Castro de Oliveira, Dario Windmöller, Hermi F. Brito, Oscar L. Malta, G.F. de Sá, W.F. Magalhães, J.C. Machado,
Tópico(s)Synthesis and characterization of novel inorganic/organometallic compounds
ResumoPositronium formation in the bimary molecular solid solutions Tb(1-x)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.
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