This thesis has involved an attempt to determine the ratio of electric-quadrupole radiation to magnetic-dipole radiation for the forbidden transition 6647A(2D5/2-2D3/2) of ionized mercury. The high resolution needed for this type of work was obtained by using a 14mm Fabry-Perot etalon and a three prism glass spectrograph, The mercury source was a heated eleotrodeless quartz discharge tube excited by an rf oscillator. A large electromagnet was used to obtain the Zeeman effect. This is the first time that the 6647A transition has been analyzed. The experimental results for the longitudinal view show agreement with predictions for the Zeeman components giving complete verification of the identity of the line but the intensity patterns show a possible disagreement with theoretical predictions for the ratio of magnetic-dipole to electric-quadrupole radiation.Ball State UniversityMuncie, IN 47306

Orientador: Agda Eunice de Souza Albas / Resumo: A busca por novas metodologias e ferramentas didáticas, aplicada às aulas, têm sido discutidos em vários trabalhos na área de Ensino de Ciências, especificadamente, no Ensino de Física. Uma alternativa tem sido o uso da aprendizagem significativa de Ausubel, utilizando o processo de ancoragem na aprendizagem dos novos conceitos, proporcionando a verificação das relações entre os conceitos gerais e os específicos. Os Mapas Mentais é uma potencial ferramenta de pensamento para verificação das relações conceituais já que trata-se de um diagrama que busca relacionar os conceitos trabalhados através de palavras-chaves organizando-os através de tópicos e subtópicos relacionando conhecimentos específicos a um assunto geral proposto na construção do Mapa Mental. Isto permite ao aluno relacionar os conteúdos, através das regras de construção dos Mapas Mentais, utilizando cores, ilustrações e pequenas sínteses dos assuntos fazendo dessa ferramenta de pensamento, uma proposta potencialmente para o acompanhamento da Aprendizagem Significativa. Este trabalho descreve o uso de Mapas Mentais, como uma possível ferramenta associada ao processo de ensino-aprendizagem, aplicados aos conceitos da Física Contemporânea, em específico, ao estudo dos Espectros Atômicos utilizando a Teoria de Aprendizagem Significativa de David Ausubel. / Abstract: The search for new methodologies and teaching tools, applied to classes, have been discussed in several researches papers in the area of Science Teaching, specifically in Physics Teaching. An alternative has been the use of meaningful learning by Ausubel, utilizing the anchoring process in learning the new concepts of this, providing verification of the relationships between general and specific concepts. The Mind Maps is a potential thinking tool for checking conceptual relationships because it is a diagram that seeks to relate the concepts worked through keywords organizing them through topics and subtopics relating specific knowledge to a general subject proposed in construction of the Mind Map. This allows the student to relate the contents, through the rules of mind map construction, using colors, illustrations and short syntheses of the subjects, making this thinking tool a potential proposal for the accompaniment of meaningful learning. This paper describes the use of Mind Maps as a possible tool associated with the teaching-learning process, applied to the concepts of Contemporary Physics, specifically, the study of Atomic Spectrums using David Ausubel's Meaningful Learning Theory. / Mestre

<p>  Based on the multichannel quantum defect method and streamlined R-matrix treatment, this thesis studies the multi-photon ionization spectrum for atomic helium and barium, and explores the electronic correlations of these atoms. For the helium atom, the above-threshold-ionization spectra have been calculated, with two linearly polarized photons, two oppositely circularly polarized photons, and three linearly polarized photons. The propensity rules for the single-photon ionization and autoionizing decay have been extended into the multi-photon region, showing that the excitation rules are not always satisfied for the most prominent channel. In a separate project, based on the spontaneous two-photon decay of the helium 1s2s 1Se excited state that has a rather long lifetime, one can create photon pairs that are entangled in time, frequency, and polarization. Experimental schemes are proposed to use them as a laser source to ionize another helium. Finally, we considered the oneand two-photon pathway coherent control of atomic helium and barium near their autoionizing levels. For the helium atom, we proposed a controlling scheme that can flip 90 % of the photocurrent by a slight change of laser frequency. For the barium atom, we computed the phase lag between 6s1/2 and 5d3/2 ionization continua, which agrees with the experimental results that a previous phenomenological model failed to reproduce. Our treatment also develops formulas to describe the effects of hyperfine depolarization on multiphoton ionization processes, and it identifies resonances that had not been observed and classified in previous experiments. <br>  </p>