Transition metal-aromatic hydrocarbon complexes were generated in a supersonic jet and studied by zero electron kinetic energy (ZEKE) photoelectron spectroscopy and theoretical calculations. The target metal complexes were identified using time-of-flight mass spectrometry, and their ionization thresholds were located via photoionization efficiency spectroscopy. ZEKE spectroscopy was used to measure the ionization energies and vibrational frequencies of the metal complexes. Their electronic states and corresponding molecular structures were determined by comparing the experimental spectra to quantum chemical calculations and Franck-Condon simulations. In this dissertation, the metal complexes of four different aromatic hydrocarbon ligands were studied: benzene (bz), naphthalene (np), biphenyl (bp) and 1-phenyl naphthalene (phnp). In these complexes, the metal atom or ion was determined to bind to either one or two -rings. Three different bonding schemes were observed in these complexes. A twofold bonding scheme was observed in M+/M-np (M = Sc, Y, Ti, Zr, Hf), while a sixfold bonding scheme was observed in Sc+/Sc-bz and M+/M-bz2 (M = Sc, Ti, V, Cr, Mo, W). In the metal-polyphenyl complexes (i.e. Sc-, La-, and Ti-bp and Sc-phnp), twelve-fold metal-ligand bonding occurred, sixfold to two -rings of the ligand. This twelve-fold bonding mechanism requires rotation of the -rings by ~ 42 o and bending of the -rings by 40 to 57 o to clamp the metal atom or ion between the two -surfaces. Although the ground state spin multiplicities of the bare metal atoms and ions varied quite extensively, the multiplicities of the metal complexes were determined to be either singlet or doublet, except for Sc+/Sc-bz, V+-bz2, Ti-np, and Zr-np, where the triplet or quartet spin multiplicities were favored. The low spin and relatively narrower range of electron-spin multiplicities in the complexes were the result of d orbital splitting, where the degeneracy of the d orbitals was broken. Thus, the valence electrons were paired in each metal d-based molecular orbital of the complex to form low-spin singlet or doublet spin states. Some complexes favored triplet and quartet multiplicities, because the energy difference between the two highest occupied molecular orbitals was smaller than the electron pairing energy.

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abstract: The absorption spectra of metal-centered phthalocyanines (MPc's) have been investigated since the early 1960's. With improved experimental techniques to characterize this class of molecules the band assignments have advanced. The characterization remains difficult with historic disagreements. A new push for characterization came with a wave of interest in using these molecules for absorption/donor molecules in organic photovoltaics. The use of zinc phthalocyanine (ZnPc) became of particular interest, in addition to novel research being done for azaporphyrin analogs of ZnPc. A theoretical approach is taken to research the excited states of these molecules using time-dependent density functional theory (TDDFT). Most theoretical results for the first excited state in ZnPc are in only limited agreement with experiment (errors near 0.1 eV or higher). This research investigates ZnPc and 10 additional porphyrin analogs. Excited-state properties are predicted for 8 of these molecules using ab initio computational methods and symmetry breaking for accurate time- dependent self-consistent optimization. Franck-Condon analysis is used to predict the Q-band absorption spectra for all 8 of these molecules. This is the first time that Franck-Condon analysis has been reported in absolute units for any of these molecules. The first excited-state energy for ZnPc is found to be the closest to experiment thus far using a range-separated meta-GGA hybrid functional. The theoretical results are used to find a trend in the novel design of new porphyrin analog molecules. / Dissertation/Thesis / Doctoral Dissertation Materials Science and Engineering 2014

Os fundamentos para os métodos algébricos unidimensionais baseados na álgebra de momentum angular su(2)(clássica e deformada) são apresentados numa forma adequada à descrição de vibrações moleculares de sistemas diatômicos e de sistemas poliatômicos planares com simetria C_{2v}. Aplicações detalhadas envolvendo os estados vibracionais e seus respectivos potenciais foram exaustivamente desenvolvidas para os dois primeiros estados eletrônicos (A-X Sigma) dos sistemas diatômicos LiH (e seus isotopômeros), NaH, KH, RbH, CsH, e Li2. Alguns outros estados eletrônicos mais excitados também foram analisados algebricamente. Os potenciais vibracionais semi-clássicos foram calculados via estados coerentes do grupo SU(2). Calculamos também fatores de Franck-Condon usando as autofun{ções de Morse diretamente, sem qualquer necessidade de linearizações. O presente trabalho é a análise algébrica mais detalhada até o momento sobre moléculas diatômicas, pois envolve um grande número de moléculas distintas e seus estados eletrônicos excitados, os quais ainda não haviam sido analisados algebricamente. Além disto, outras propriedades físicas, como os fatores de Franck-Condon e potenciais vibracionais foram discutidos aqui em detalhes pela primeira vez. O propósito deste trabalho foi de servir como um laboratório para futuras aplicações de modelos algébricos unidimensionais a sistemas moleculares maiores, onde suas potencialidades e, principalmente, suas limitações pudessem ser testadas de forma clara. Além disto, devemos destacar também o aumento expressivo na quantidade de trabalhos sobre moléculas diatômicas e triatômicas devido à importância destas em questões de interesse mundial, como o efeito estufa, e questões de relevância acadêmica, como a espectroscopia em tempo real e de moléculas frias.

Orientadores: Helena Jank, Esdras Rodrigues Silva / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Artes / Made available in DSpace on 2018-08-03T17:03:33Z (GMT). No. of bitstreams: 1 Casado_AlexandreAlves_M.pdf: 5623149 bytes, checksum: c9813f6cd2fd592df85eae6834db7978 (MD5) Previous issue date: 2003 / Resumo: Este trabalho focaliza a sonata para piano e violino de César Franck e as propostas de arcadas e dedilhados contidas em quatro edições distintas. Dividi-se em quatro capítulos. No capítulo I, .0 compositor", apresentamos uma sucinta biografia de C. Franck, dividida em três partes: .A época", .0 homem" e · A obra". A época contém a desaição do ambiente musical francês no início do século XIX, que constituiu o pano de fundo para a obra do compositor. Em .0 homem", observamos sua vida pessoal e formação. .A obra" focaliza seu estilo de composição e influências recebidas. No capítulo 11 -.A Sonata", apresentamos uma análise desta obra, do ponto de vis1a estrutural, desaevendo suas características harmônicas e formais. No capítulo 11I - .Os revisores", desaevemos e apresentamos informações a respeito de cada um dos revisores. O capitulo IV, .Arcadas e dedilhados" contém uma análise técnica das arcadas e dedilhados propostos pelos quatro revisores, comparando-os entre si, comentando as possíveis motivações que os levaram a fazer estas escolhas, e suas conseqüências musicais. Esta análise pode dar ao leitor uma consciência mais profunda da importância da reflexão sobre dedilhados e arcadas que imprimem à execução o toque pessoal do artista, contribuindo para que possa chegar a uma interpretação melhor e bem fundamentada, do ponto de vista estético e estilístico / Mestrado / Musica / Mestre em Artes

Abstract Elementary experiments of atomic physics and quantum optics can be reproduced on a circuit board using elements built of superconducting materials. Such systems can show discrete energy levels similar to those of atoms. With respect to their natural cousins, the enhanced controllability of these ‘artificial atoms’ allows the testing of the laws of physics in a novel range of parameters. Also, the study of such systems is important for their proposed use as the quantum bits (qubits) of the foreseen quantum computer. In this thesis, we have studied an artificial atom coupled with a harmonic oscillator formed by an LC-resonator. At the quantum limit, the interaction between the two can be shown to mimic that of ordinary matter and light. The properties of the system were studied by measuring the reflected signal in a capacitively coupled transmission line. In atomic physics, this has an analogy with the absorption spectrum of electromagnetic radiation. To simulate such measurements, we have derived the corresponding equations of motion using the quantum network theory and the semi-classical approximation. The calculated absorption spectrum shows a good agreement with the experimental data. By extracting the power consumption in different parts of the circuit, we have calculated the energy flow between the atom and the oscillator. It shows that, in a certain parameter range, the absorption spectrum obeys the Franck-Condon principle, and can be interpreted in terms of vibronic transitions of a diatomic molecule. A coupling with a radiation field shifts the spectral lines of an atom. In our system, the interaction between the atom and the field is nonlinear, and we have shown that a strong monochromatic driving results in energy shifts unforeseen in natural or, even, other artificial atoms. We have used the Floquet method to calculate the quasienergies of the coupled system of atom and field. The oscillator was treated as a small perturbation probing the quasienergies, and the resulting absorption spectrum agrees with the reflection measurement.

Thesis (M.A.)--Boston University

Thesis (D.M.A.)--Boston University / PLEASE NOTE: Boston University Libraries did not receive an Authorization To Manage form for this thesis or dissertation. It is therefore not openly accessible, though it may be available by request. If you are the author or principal advisor of this work and would like to request open access for it, please contact us at open-help@bu.edu. Thank you. / 2031-01-01

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