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dc.contributor.advisorBettega, Marcio Henrique Franco, 1964-
dc.contributor.authorJoucoski, Emerson
dc.contributor.otherUniversidade Federal do Paraná. Setor de Ciências Exatas. Programa de Pós-Graduaçao em Física
dc.date.accessioned2015-12-10T14:04:22Z
dc.date.available2015-12-10T14:04:22Z
dc.date.issued2002
dc.identifier.urihttp://hdl.handle.net/1884/40555
dc.descriptionOrientador : Márcio Henrique Franco Bettega
dc.descriptionDissertação (mestrado) - Universidade Federal do Paraná
dc.description.abstractResumo: We present results of calculations of integral cross sections, differential cross sections and momentum transfer cross sections for elastic scattering of low-energy electrons by NF3 and SnY4 (Y=C1, Br, I) molecules. Our calculations were performed with the Schwinger multichannel method with pseudopotentials at the fixed-nuclei static-exchange approximation. For e~-NF3 collisions we have compared our results with the experimental results of Boesten et al. and with the theoretical results of Rescigno, obtained with the complex Kohn variational method, and found in general good agreement. We have also obtained the symmetry decomposition for the NF3 integral cross section according to the C3t, group, for the Ai, E, and A2 representations. We have found two independet shape resonances for NF3: one for the A4 representation and the other for the E representation. We have also found that the NF3 molecule dissociates through electron attachment along the N-F bond. The shape resonance for the E representation is responsible for this dissociation that produces mainly F" ions. In order to improve the position of the shape resonances, we have also included polarization effects in the e- -NF3 collision cross sections calculations and compared our results with those of Boesten et al. and Rescigno. We also present results of our study on electron scattering by SnY4 (Y=C1, Br, I) molecules. We have covered the energy range from 5 eV up to 40 eV. We have carried out a comparative study of the cross sections of the XY4 (X=C, Si, Ge, Sn; Y=C1, Br, I) molecules, using for this purpose some previous published results. We have obtained the symmetry decomposition of the integral cross section according to the T^ group for each one of the above molecules. Our results show that the cross section for a given representation of the T d group presents the same pattern for all studied carbon, silicon, germanium, and tin tetrahalides.
dc.description.abstractAbstract: We present results of calculations of integral cross sections, differential cross sections and momentum transfer cross sections for elastic scattering of low-energy electrons by NF3 and SnY4 (Y=C1, Br, I) molecules. Our calculations were performed with the Schwinger multichannel method with pseudopotentials at the fixed-nuclei static-exchange approximation. For e~-NF3 collisions we have compared our results with the experimental results of Boesten et al. and with the theoretical results of Rescigno, obtained with the complex Kohn variational method, and found in general good agreement. We have also obtained the symmetry decomposition for the NF3 integral cross section according to the C3t, group, for the Ai, E, and A2 representations. We have found two independet shape resonances for NF3: one for the A4 representation and the other for the E representation. We have also found that the NF3 molecule dissociates through electron attachment along the N-F bond. The shape resonance for the E representation is responsible for this dissociation that produces mainly F" ions. In order to improve the position of the shape resonances, we have also included polarization effects in the e- -NF3 collision cross sections calculations and compared our results with those of Boesten et al. and Rescigno. We also present results of our study on electron scattering by SnY4 (Y=C1, Br, I) molecules. We have covered the energy range from 5 eV up to 40 eV. We have carried out a comparative study of the cross sections of the XY4 (X=C, Si, Ge, Sn; Y=C1, Br, I) molecules, using for this purpose some previous published results. We have obtained the symmetry decomposition of the integral cross section according to the T^ group for each one of the above molecules. Our results show that the cross section for a given representation of the T d group presents the same pattern for all studied carbon, silicon, germanium, and tin tetrahalides.
dc.format.extent105p. : il., grafs.
dc.format.mimetypeapplication/pdf
dc.languagePortuguês
dc.subjectTeses
dc.subjectEspalhamento elastico
dc.subjectFisica
dc.subject.ddcT 530.416
dc.titleEspalhamento elástico de elétrons por moléculas de NF3 e SnY4 (Y=Cl, Br, I)
dc.typeDissertação


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