Estudo da fotoionização de radicais e reações íon-molécula de interesse planetário, através de radiação VUV síncrotron e laser

• Ano de defesa: 2011
• Autor(a) principal: Miranda, Bárbara Kelly Cunha de
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Programa de Pós-graduação em Física; Física
• Palavras-chave em Português: Fotoionização; Radiação VUV; Síncrotron; CNPQ::CIENCIAS EXATAS E DA TERRA::FISICA
• Link de acesso: https://app.uff.br/riuff/handle/1/19378

This work has the motivation to provide experimental data relevant to the interpretation of the chemistry of planetary ionospheres, particularly for the largest satellite of Saturn, Titan. Here we have a particular interest in studying the reactivity of excited ionic species. The first part of this work concerns the production of CH+ 3 and CF+3 state selected cations by VUV photoionization of neutral species and the second part, the reactions of state selected cations with molecules : O+ with methane and N+(3P) with C3H4, C3H6 and C3H8. The study of the preparation of the CH+3 and CF+3 cations in selected vibrational levels was performed by using the TPEPICO coincidence technique and VUV radiation at the french synchrotron, SOLEIL. A PFI-ZEKE spectrometer, that allowed us to obtain a resolution down to 0.84 cm-1 was constructed to conduct additional studies involving laser VUV radiation at the Laser Center of the University Paris Sud XI, at Orsay in France. Experiments to determine the influence of the O+ (2S,2D,2P) cation excitation on its reaction with methane were performed using the TPEPICO coincidence and the guide ion beam technique. These experiments were performed on the VUV DESIRS beamline at the synchrotron SOLEIL. Rate constants and products branching ratio for the reacion of N+(3P) with C3H4, C3H6 and C3H8 were measured with the SIFT technique in a small commercial apparatus at the Institute of Physical Chemistry J. Heyrovský in Prague, Czech Republic.