Estudos espectroscopicos em atomos e moleculas : calculos de forças de osciladores e tempos de vida para ions de Si, medidas de momento de recuo de ions em atomos de Cs resfriados a laser e medidas de multicoincidência em moleculas de N2 e O2

AUTOR(ES)
DATA DE PUBLICAÇÃO

2003

RESUMO

This thesis comprises atomic and molecular physics studies, both theoretical and experimental. Weighted oscillator strengths and lifetimes were calculated for the following silicon ions: Si I, Si XI, Si XII and Si XIII. The calculations were carried out in a multiconfiguration Hartree-Fock relativistic aproach. The eletrostatic parameters were optimized by a least-squares procedure in order to improve the adjustment to experimental energy levels and transitions wavelengths. Another work in the atomic physics area was the construction of a new time-of-flight spectrometer to measure ion recoil momentum in laser-cooled atoms, after photoionization by synchrotron radiation. This is a pioneering work that opens up a new research area. With this equipment ion recoil momentum were measured for the Cs + ion, and it was possible to determine the b assymetry parameter in the energy range studied, 13 to 40 eV. The molecular physics studies comprised multicoincidence measurements (PEPICO and PEPIPICO) in N2 and O2 near the ionization thresholds N 1s and O 1s, respectively. Total Ion Yield (TIY) spectra were also obtained for these molecules. Coincidence spectra (PEPICO) for some aminoacids in their gas phase were also taken for the first time

ASSUNTO(S)

fotoionização atomos - resfriamento radiação sincrotronica espectroscopia de ultravioleta espectroscopia molecular espectroscopia atomica

ACESSO AO ARTIGO

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