Navegando por Autor "Francisco, Guilherme de Sousa"

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    Métodos de modelagem molecular para estudo e planejamento de compostos com propriedades óticas
    (Universidade Federal de Goiás, 2017-07-14) Francisco, Guilherme de Sousa; Moreira, Nilton Luis; http://buscatextual.cnpq.br/buscatextual/visualizacv.do? id=K4735418E8; Romualdo, Lincoln Lucilio; http://buscatextual.cnpq.br/buscatextual/visualizacv.do? id=K4769026U8; Romualdo, Lincoln Lucilio; Brito, Braulio Gabriel Alencar; Vieira, Jorge Luiz
    In recent decades, the search for materials with nonlinear optical (NLO) properties was intensified and currently covers a large variety of materials such as semiconductor multilayer structures, organic, inorganic and organometallic compounds. Non-linear optical materials have been of great interest in Physics and Chemistry of materials due to its potential applications in new technologies such as, electro-optical devices with optical keys, frequency converters and electro-optical modulators and photonic devices engineering. In this work we used Hartree Fock methods (HF) and Density Functional Theory (DFT), as implemented in the Gaussian09 package to obtain the geometric properties, electronics and optical from the compounds 4-nitroaniline, chalcone and malonic acid Salicyl-hydrazone ((HO_2 C)(C_6 H_3)(OH)NHNCH(COOH)_2). As the latter compound is not in literature, for the first time is presented a possible geometric structure, which the simulation shows a planar structure with asymmetry due to its “push-pull” character which are important characteristics for the second harmonic generation (SHG). Some properties were obtained, such as the dipole moment, polarizability and hyperpolarizabilities of the first compound order. Preliminary results show that the DFT produces larger values of hyperpolarizability by comparing with the results obtained by the Hartree Fock method. The hyperpolarizability is sensitive to the choice of the system of calculation, so in this work we used several arrangements of the basic functions as Pople Nernst, in addition to others found in the literature, in order to obtain the best possible description of the studied system.