Abstract This thesis deals with the rotation-vibration theory and high resolution infrared spectroscopy of semirigid C3 molecules. Semirigid molecules form a class of molecules which are strongly bound with one well defined structure, and without low frequency internal motions. The theory, as well as the experimental studies of semirigid molecules are of special importance in the field of rotation-vibration spectroscopy. They provide a good starting point for interpreting and analyzing the spectra of practically all types of molecules. In this work, the theory is reviewed fromthe standpoint of one particular molecule, 13CH3I, which is a prolate symmetric top with C3 symmetry. The origin and the properties of the rotation-vibration Hamiltonian are discussed in detail. Molecular symmetry plays an important role in these studies. The expansion of the Hamiltonian for nuclear motion in powers of the vibrational operators converges rapidly as numerical examples thoughout the treatment indicate. The molecule is thus a good subject for the perturbation calculations, also reviewed here in detail. 13CH3I can be considered as a model example of semirigid molecules. From the spectroscopic point of view, this thesis is a study of the six fundamental bands of 13CH3I. The rotational analysis of the vibrational ground state is first given. Special attention is paid to obtaining the axial rotational constants which are problematic for symmetric top molecules. The relatively high energy level density of 13CH3I leads to several resonances. The fundamental bands, especially the higher ones, must therefore be treated as parts of band systems. Care is paid to properly take into account the effects of the near-lying vibrational levels on the constants of the fundamentals. Certain ambiguities in the rotation-vibration Hamiltonian of 13CH3I are also discussed.

Este trabalho aborda, de uma forma geral, os sistemas estruturais normalmente adotados no projeto de cúpulas metálicas. Foi dado ênfase a um arranjo derivado do sistema Schwedler, recentemente utilizado em projetos desenvolvidos no interior do estado de São Paulo. O trabalho pode ser divido em duas partes, a primeira delas versando sobre as ligações que compunham o sistema estrutural estudado, e a segunda versando sobre a influência dessas ligações no comportamento da estrutura e sobre a influência da forma de contraventamento. As ligações foram estudadas sob dois aspectos diferentes, que foram: a) revisão e aperfeiçoamento dos critérios de dimensionamento adotados em algumas ligações, e b) proposição de modelos para descrição do comportamento momento-rotação de ligações com dupla tala de alma parafusada e de aparelhos de apoio. A influência do tipo de contraventamento e da rigidez das ligações foi investigada por meio do efeito exercido nos deslocamentos verticais e na distribuição de esforços internos da estrutura. Para tanto, foram utilizados programas computacionais de uso já consagrado, cujos resultados foram comparados entre si. / In a general way, this work deals with structural systems usually adopted in the project of metallic domes. Emphasis was given to a derived arrangement derived of the Schwedler system, recently used in projects developed the state of São Paulo. The work can be divided in two parts, the first one is about the connections that compose the structural system studied, and second one treats the influence of those connections in the structure behavior and the influence in the brace configuration. The connections were studied under two different aspects, that were: a) revision and improvement of the design criteria adopted in some connections, and b) proposition of models for the momentrotation description for double plate connections of web. The influence of the brace type and of the rigidity of the connections were investigated by means of the effect in the vertical displacements and in the distribution of internal efforts of the structure. So, two commercial softwares were used, and the results were compared.

Este trabalho aborda, de uma forma geral, os sistemas estruturais normalmente adotados no projeto de cúpulas metálicas. Foi dado ênfase a um arranjo derivado do sistema Schwedler, recentemente utilizado em projetos desenvolvidos no interior do estado de São Paulo. O trabalho pode ser divido em duas partes, a primeira delas versando sobre as ligações que compunham o sistema estrutural estudado, e a segunda versando sobre a influência dessas ligações no comportamento da estrutura e sobre a influência da forma de contraventamento. As ligações foram estudadas sob dois aspectos diferentes, que foram: a) revisão e aperfeiçoamento dos critérios de dimensionamento adotados em algumas ligações, e b) proposição de modelos para descrição do comportamento momento-rotação de ligações com dupla tala de alma parafusada e de aparelhos de apoio. A influência do tipo de contraventamento e da rigidez das ligações foi investigada por meio do efeito exercido nos deslocamentos verticais e na distribuição de esforços internos da estrutura. Para tanto, foram utilizados programas computacionais de uso já consagrado, cujos resultados foram comparados entre si. / In a general way, this work deals with structural systems usually adopted in the project of metallic domes. Emphasis was given to a derived arrangement derived of the Schwedler system, recently used in projects developed the state of São Paulo. The work can be divided in two parts, the first one is about the connections that compose the structural system studied, and second one treats the influence of those connections in the structure behavior and the influence in the brace configuration. The connections were studied under two different aspects, that were: a) revision and improvement of the design criteria adopted in some connections, and b) proposition of models for the momentrotation description for double plate connections of web. The influence of the brace type and of the rigidity of the connections were investigated by means of the effect in the vertical displacements and in the distribution of internal efforts of the structure. So, two commercial softwares were used, and the results were compared.

Nanoporous organic polymers, including hypercrosslinked polymers (HCPs), covalent organic frameworks (COFs), polymers of intrinsic microporosity (PIMs), and conjugated microporous polymers (CMPs) etc., are considered good candidates for potential gas storage and gas separation applications. Porosities and surface areas of a series of semirigid alternating copolymers, which contained tert-butyl carboxylate-functionalized stilbene or tert-butyl carboxylate-functionalized styrene, and maleic anhydride or tert-butyl carboxylate-functionalized phenyl maleimide, were investigated using nitrogen sorption/desorption isotherms at 77 K and molecular simulations. These alternating copolymers were found to have Brunauer-Emmett-Teller (BET) surface areas in the range of 20-40 m2/g. Surface areas of these alternating copolymers increased as the steric crowding of the polymer backbone increased, which was the result of introducing extra phenyl rings and/or N-phenyl substituent maleimide units. Surface areas were found to increase as the persistence length increased. A series of HCPs containing functionalized stilbene and N-substituted phenyl maleimide were synthesized via free radical suspension polymerization. The incorporation of these functionalized, chain stiffening, Tg enhancing comonomers raised the Tgs of precursor polymers before they were crosslinked. Surface areas of these HCPs, obtained from nitrogen adsorption/desorption isotherms at 77 K, were up to 1058 m2/g. However, the surface areas of these HCPs were systematically lower than the controls. The high rigidity of the polymer backbone, which was the result of incorporating Tg enhancing comonomer, likely affected the chain mobility of the precursor polymer, decreased the efficiency of post-crosslinking reactions, and thus resulted in lower surface areas. Amine-functionalized styrene/stilbene polymers were prepared via free radical polymerization or post-modification. Amine-containing silica-based sorbents were prepared using the impregnation method. Sorption of CO2 by these materials was tested using TGA and compared with control samples. Both high amine content and certain levels of surface area were found to be important for a sorbent to achieve high CO2 uptake. Highest CO2 uptake (12 wt%) under our testing condition in these materials was achieved by an amine-containing silica sorbent. / Ph. D.