Análise comparativa da aproximação da carga pontual para íons lantanídeos (III) na modelagem pelo método DFT de estados excitados de ligantes em complexos

Abstract

The objective of this work was to evaluate the performance of the point-charge for lanthanide(III) ions in the DFT modeling of excited states of ligands in some complexes, especially with beta-diketonate-type ligands. For this, TD-DFT calculations were performed via TDA for the excited states varying some parameters: point-charge (between +3.0 and +4.0), the basis functions (STO-3G, 6-31G, 6-31G, 6-31G(d)) and functional (B3LYP and PBE0). The results obtained were compared with the literature (International Journal of Quantum Chemistry, v. 90, pp. 924-932, 2002) and it was observed that the applied methodology presented divergent results than expected in the systematic shift of the spectral bands towards the increasing of point-charge value. Despite this, there are spectral formats consistent with experimental data. It was noticed the good behavior of the point-charge model relationed to the energies of the orbitals and the greater distortion that a high point-charge value causes in the composition of the orbitals.