Cálculo de propriedades magnéticas de complexos de metais de transição usando a teoria do funcional da densidade

• Ano de defesa: 2013
• Autor(a) principal: Florencio, Antonio da Silva
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Programa de Pós-graduação em Química; Química
• Palavras-chave em Português: Magnetismo molecular; Cálculos DFT; Broken symmetry; Fragmentos moleculares; Orbitais magnéticos; Densidade de spin.; Metal de transição; propriedade magnética; Simetria; Funcional de densidade; Estrutura molecular (Química inorgânica); Molecular Magnetism; DFT calculations; Molecular fragments; Magnetic orbitals; Spin density.; Transition metal; magnetic property; Symmetry; Molecular magnetism; Density functional; Molecular structure (inorganic chemistry); CNPQ::CIENCIAS EXATAS E DA TERRA::QUIMICA
• Link de acesso: https://app.uff.br/riuff/handle/1/20712

This work presents results of DFT calculations that contributed to the understanding of magnetic interactions present in molecular magnetic systems. Firstly, the magnetic coupling between dimmers formed by ions and/or radicals with S = 1/2 was modeled. In a second step, the magnetic coupling between more complex dimmers, formed by metal ions with magnetic spin moment S ≠ 1/2, as Fe(III) and Mn(III). Finally, were analyzed more complex systems, containing four magnetic centers, as {Ni4O4}, {Co4O4}, {Mn4O6}, {Mn2Co2O6}, and a Cu(II) - nitronyl nitroxide chain were also studied. The broken symmetry and the fragment approaches were used to calculate the magnetic coupling constant of these systems. Moreover, the studies of the electronic structure of thesesystems allowed us to rationalize the pathways for magnetic interactions. In simpler systems methodology employing plane waves was applied and the result using periodic boundary conditions was compared with those obtained using molecular approaches. The magneto-structural relationship performed for some systems showed the strong dependence of the magnetic properties on small structural changes, especially bond angles.