Journal ArticleDOI
Solid Eu(III) complexes studied by positron annihilation, optical and Mössbauer spectroscopies: insights on the positronium formation mechanism.
F. Fulgêncio,F.C. de Oliveira,F.C. de Oliveira,F.F. Ivashita,A. Paesano,Dario Windmöller,A. Marques-Netto,W.F. Magalhães,José C. Machado +8 more
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TLDR
Strong evidences that the electronic delocalization does not occur at both temperatures are found and suggest that the absence of positronium in Eu(III) complexes cannot be explained by a ligand/metal charge transfer process.About:
This article is published in Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy.The article was published on 2012-06-15. It has received 15 citations till now. The article focuses on the topics: Positronium.read more
Citations
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Journal ArticleDOI
The Role of the Ligand-to-Metal Charge-Transfer State in the Dipivaloylmethanate-Lanthanide Intramolecular Energy Transfer Process
Yolanda C Miranda,Leide L. A. L Pereira,José H. P Barbosa,Hermi F. Brito,Maria C.F.C. Felinto,Oscar L. Malta,Wagner M. Faustino,Ercules E.S. Teotonio +7 more
TL;DR: In this paper, the photoluminescent properties of the monomeric and dimeric complexes are dependent on the energy positions of the low-lying ligand-to-metal charge transfer (LMCT) state, which may be correlated with the chelating and chelate bridging coordination modes of the dpm ligand.
Journal ArticleDOI
Synthesis of amino acid iodine charge transfer complexes in situ methanolic medium: Chemical and physical investigations
K.R. Mahmoud,Moamen S. Refat,Moamen S. Refat,Taher Sharshar,Taher Sharshar,Abdel Majid A. Adam,El-Sayed A. Manaaa +6 more
TL;DR: In this article, a new procedure for preparation of glycine and alanine triiodide charge transfer complexes by solid-solid interactions using different spectroscopic tools was investigated, which revealed that most of PAL and PADB parameters are strongly correlated with the molecular weight of the prepared CT complexes.
Journal ArticleDOI
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
F. Fulgêncio,F.C. de Oliveira,F.C. de Oliveira,Dario Windmöller,Hermi F. Brito,Oscar L. Malta,G.F. de Sá,W.F. Magalhães,José C. Machado +8 more
TL;DR: A strong linear correlation between the (5)D(4) Tb(iii) energy level excited state lifetime and the positronium formation probability has been observed, indicating that the ligand-to-metal charge transfer LMCT states act in both luminescence quenching and positronia formation inhibition, as previously proposed.
Journal ArticleDOI
Coordination Geometrical Effect on Ligand-to-Metal Charge Transfer-Dependent Energy Transfer Processes of Luminescent Eu(III) Complexes
Pedro Paulo Ferreira da Rosa,Shiori Miyazaki,Haruna Sakamoto,Yuichi Kitagawa,Kiyoshi Miyata,Tomoko Akama,Masato Kobayashi,Koji Fushimi,Ken Onda,Tetsuya Taketsugu,Yasuchika Hasegawa +10 more
TL;DR: In this paper, the LMCT-dependent energy transfer processes of seven and eight-coordinated europium (Eu(III) ion were demonstrated for the first time using temperature-dependent and time-resolved emission lifetime measurements of 5D0 → 7FJ transitions of Eu (III) ions.
Journal ArticleDOI
Luminescence and positron spectroscopies studies of tris(2,2,6,6-tetramethyl-3,5-heptanedionate) europium(III) and terbium(III) complexes containing 2-pyrrolidone as coligand
Alex S. Borges,F. Fulgêncio,Jeferson G. Da Silva,Tatiana A. Ribeiro-Santos,Renata Diniz,Dario Windmöller,W.F. Magalhães,Maria Helena Araujo +7 more
TL;DR: In this paper, the synthesis, characterization, luminescent properties and positronium formation yields of europium and terbium(III) complexes of stoichiometric formula Ln(dpm)3(2-pyr), where: Ln = Eu and Tb, dpm = 2,2,6,6-tetramethyl-3,5-heptanedionato (dipivaloylmethanate) ion, a β-diketonate ligand, and 2 pyr = γ-l
References
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Journal ArticleDOI
Spectroscopic properties and design of highly luminescent lanthanide coordination complexes
G.F. de Sá,Oscar L. Malta,C. de Mello Donegá,Alfredo M. Simas,Ricardo L. Longo,P.A. Santa-Cruz,E. F. da Silva +6 more
TL;DR: In this paper, the development of efficient light conversion molecular devices (LCMDs) based on lanthanide complexes is reviewed, with emphasis on the work of our group, who have adopted a strategy based upon both theoretical and experimental (synthesis and methodological) investigations.
Journal ArticleDOI
Positronfit Extended: A New Version of a Program for Analysing Positron Lifetime Spectra
TL;DR: The POSITRONFIT EXTENDED extended version of this program is available from the CPC Program Library, Queen's Uni, Toronto, Ontario, Canada, Canada.
Journal ArticleDOI
Spur reaction model of positronium formation
TL;DR: In this article, a new model of positronium (Ps) formation is proposed, which is based on a reaction between a positron and an electron in the positron spur.
Journal ArticleDOI
Observation of electron hopping in 151Eu3S4 by Mössbauer spectroscopy
TL;DR: In this paper, an electron hopping model together with an exchange narrowing formula yield a temperature dependent hopping time characteristic of an activation process, and the activation energy found is 0.24 eV.