Document Detail


Solid Eu(III) complexes studied by positron annihilation, optical and Mössbauer spectroscopies: Insights on the positronium formation mechanism.
MedLine Citation:
PMID:  22466013     Owner:  NLM     Status:  Publisher    
Abstract/OtherAbstract:
In this work, positron annihilation lifetime (PALS), Doppler broadening annihilation radiation lineshape (DBARL), Mössbauer and optical spectroscopies measurements were performed in Eu(III) dipivaloylmetanate complex, Eu(dpm)(3), at 295 and 80K. The Eu(dpm)(3) complex is not luminescent at 298K and does not form positronium. On the other hand, it is highly luminescent at 80K, but still does not form positronium. The absence of positronium formation at 80K cannot be explained by a ligand/metal charge transfer process. We found strong evidences that the electronic delocalization does not occur at both temperatures. Despite the Mössbauer results being inconclusive regarding the Eu(III)/Eu(II) reduction hypothesis, previous results showing positronium formation in other Eu(III) complexes suggest that this process is not occurring. Thus, more studies are needed to explain the absence of positronium in Eu(III) complexes.
Authors:
F Fulgêncio; F C de Oliveira; F F Ivashita; A Paesano; D Windmöller; A Marques-Netto; W F Magalhães; J C Machado
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Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2012-2-25
Journal Detail:
Title:  Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy     Volume:  92C     ISSN:  1873-3557     ISO Abbreviation:  -     Publication Date:  2012 Feb 
Date Detail:
Created Date:  2012-4-2     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  9602533     Medline TA:  Spectrochim Acta A Mol Biomol Spectrosc     Country:  -    
Other Details:
Languages:  ENG     Pagination:  415-418     Citation Subset:  -    
Copyright Information:
Copyright © 2012 Elsevier B.V. All rights reserved.
Affiliation:
Laboratório de Espectroscopia de Aniquilação de Pósitron - Departamento de Química - ICEx/UFMG, C. P. 702, CEP 31270-901 Belo Horizonte, MG, Brazil.
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