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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Secção de choque total absoluta do espalhamento de elétrons por Metanol e Etanol

Silva, Daniel Gustavo Mesquita da 06 April 2009 (has links)
Submitted by Renata Lopes (renatasil82@gmail.com) on 2017-06-09T15:24:44Z No. of bitstreams: 1 danielgustavomesquitadasilva.pdf: 1286713 bytes, checksum: 02c113ea7352199324c4ee67f18311bf (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2017-06-29T12:06:17Z (GMT) No. of bitstreams: 1 danielgustavomesquitadasilva.pdf: 1286713 bytes, checksum: 02c113ea7352199324c4ee67f18311bf (MD5) / Made available in DSpace on 2017-06-29T12:06:17Z (GMT). No. of bitstreams: 1 danielgustavomesquitadasilva.pdf: 1286713 bytes, checksum: 02c113ea7352199324c4ee67f18311bf (MD5) Previous issue date: 2009-04-06 / Neste trabalho foram obtidas Secções de Choque Totais Absolutas (SCTA) para moléculas de Etanol e Metanol utilizando um aparelho desenvolvido no Laboratório de Espectroscopia Atômica e Molecular do DF/UFJF, que emprega a técnica de transmissão linear. As medidas foram realizadas para o Metanol e Etanol cobrindo as energias de impacto de 70, 80, 90, 100, 150, 200, 250, 300, 350, 400 e 500 eV e também de 60 eV para o Etanol. A resolução de energia em todas as medidas foi de 0,6 eV (FWHM) e a incerteza no cálculo das SCTs foi estimada em 5%. A faixa de pressão na célula de espalhamento foi mantida entre 1 a 4mTorr. Os elétrons que sofreram processos de colisões inelásticas podem ser descriminados daqueles que não sofreram nenhum processo de interação com o alvo por um analisador cilíndrico dispersivo 127º, que tem a finalidade de selecionar os elétrons que serão detectados pelo Coletor de Faraday. Medindo a intensidade do feixe de elétrons atenuados, a SCTA pode ser obtida aplicando a Lei de Lambert Beer. Os dados foram obtidos através de um procedimento estatístico envolvendo uma série de 4 a 7 sessões de medidas, os valores obtidos foram utilizados para encontrar a SCT para uma determinada energia definida. Além das medidas experimentais, nós determinamos SCT utilizando a Regra da Aditividade. Nós também avaliamos nossos dados experimentais usando uma fórmula de dois parâmetros (Curva de Born) para cada gás. Nossos dados experimentais concordam com a maioria dos dados publicados na literatura. Não existem dados reportados na literatura de SCT para a molécula do Etanol (C2H5OH). / We have measured the absolute Total Cross Section (TCS) for methanol and ethanol molecules using an apparatus manufactured at the Molecular Spectroscopy Laboratory at DF/UFJF, which employ the linear transmission technique. The experimental data were taken at incident electron energies of 70, 80, 90, 100, 150, 200, 250, 300, 350, 400 and 500 eV for methanol and ethanol and also of 60 eV for ethanol. The energy resolution in all measurements was 0,6 eV (FWHM) and the overall systematic uncertainty at the TCS were evaluated to be less than 5%. The pressure range in the scattering cell was chosen between 1 and 4mTorr. Those electrons which passed the exit orifice of the chamber were discriminated with a 127o cylindrical energy selector coupled with an entrance set of electrostatic lenses and detected by a Faraday cup. Measuring the attenuation of intensity of the projectile-particle beam transmitted through the target volume, the absolute TCS for a given impact energy was derived from the Beer-Lambert law. The measurements were carried out for a given energy in a series of alt least 4 runs, each one taking at least 7 values and an averaging procedure was applied to derive the final total cross section at a particular energy. Besides the experimental measurements, we have additionally determined TCS using the Additivity Rule. We have also evaluated our experimental data using a fitting procedure with the Born-like formula containing two parameters for each gas. Our experimental data are in good agreement with the majority of previous measurements published in the literature. There are no previous reports of experimental electron scattering Total Cross Section C2H5OH in the literature.

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