Interações hiperfinas em catalisadores metálicos

Saitovitch, H.; Silva, Paulo R. J.; Passos, Fabio B.

doi:10.1590/s0100-40422005000300027

Cited by 4 publications

(2 citation statements)

References 3 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…A metodologia descrita a seguir, da parte experimental da espectroscopia de correlação angular gama-gama perturbada (subcapítulo 3.1), foi baseada nas seguintes referências bibliográficas [49][50][51][52][53].…”

Section: -Metodologia Experimentalunclassified

Investigação de interações hiperfinas em pó e filmes finos de dióxido de háfnio pela técnica de correlação angular gama-gama perturbada

Rossetto¹

View full text Add to dashboard Cite

Hyperfine interactions in the powder samples and nanostructured thin films of hafnium dioxide have been studied through the perturbed angular correlation (PAC) technique in order to perform a systematic study of the behavior of quadrupole parameters with the annealing temperature. The PAC measurements were performed with the probe. The probe was produced by the neutron irradiation in the IEA-R1 nuclear reactor of IPEN. Samples were prepared using sol-gel chemical process. The samples were analyzed by X-ray diffraction, SEM and EDS. The powder samples were all produced in the Laboratory of Hyperfine Interactions of IPEN, however the thin film with a thickness of was produced by the Lasers and Applications Center (CLA) of IPEN and the thin film of a thickness of were produced by the Hyperfine Interactions Laboratory of the Lisbon University. All the measurements were perform at room temperature and showed that the monoclinic phase is present in all the samples and their fraction tends to increase with increasing annealing temperature to which the samples were submitted. Some of the samples were doped with 3d elements Co and Fe in order to observe the possible existence of ferromagnetism at room temperature.

show abstract

Section: -Metodologia Experimentalunclassified

Investigação de interações hiperfinas em pó e filmes finos de dióxido de háfnio pela técnica de correlação angular gama-gama perturbada

Rossetto¹

View full text Add to dashboard Cite

show abstract

“…Em decorrência disso, a detecção das radiações-γ, guardadas as eventuais flutuações experimentais, apresenta um padrão isotrópico de intensidade. -γ 2 ) como função do ângulo ( ) medido entre as direções da emissão seqüencial destas duas radiações[28,31]. Hamiltoniana deve ser diagonalizada para cada valor de η pois os operadores de momento angular I = I x iI y projetam transições entre subestados m diferentes.…”

unclassified

Aplicação da espectroscopia de correlação angular perturbada na investigação de interações hiperfinas em compostos de háfnio, indio e cádmio com os ligantes F1-, OH1- e EDTA

Amaral¹

View full text Add to dashboard Cite

In this study the hyperfine parameters, including the dynamical nature, Perturbed Angular Correlation (PAC) spectroscopy was used to measure the hyperfine parameters in molecules of ligand compounds in solutions. The measurements were carried out at 295 K and 77 K using 111 In→ 111 Cd, 181 Hf→ 181 Ta and 111m Cd→ 111 Cd, as probe nuclei. Samples were prepared by adding a small volume of radioactive solution containing the probe nuclei in aqueous solution, buffer solution and ethylenediaminetetraacetic acid (EDTA) used as a ligand with pH 4.3 which correspond to the pH of the saturated EDTA solution and in buffer solution with pH between 9 and 10. The results made possible to understand the impact of each method for PAC measurements. Finally a comparative analysis for the several methods of inserting of the probe nuclei in the sample was made, considering chemical and nuclear aspects. The lack of measurements in this kind of samples justifies the importance of the obtained results.

show abstract