Desenvolvimento e aplicação do LUMPAC 2.0 no estudo da luminescência em compostos de Eu 3+

Abstract

The first version of LUMPAC (LUMinescence PACkage) was released by the Pople Laboratory (UFS) in 2014, with the objective of being a user-friendly program for studying luminescent properties, particularly for Eu3+ compounds. The implementation of new tools for the theoretical investigation of trivalent lanthanide ion (Ln3+) properties motivated the development of version 2.0 of LUMPAC in the present work. Among the new features, the following stand out: the possibility of performing multiple parallel calculations, the study of additional energy transfer (ET) channels, the calculation of ET rates for ligand-Tb3+systems, and the rendering of molecular orbitals for the characterization of excited states. During the development process, several features in LUMPAC 2.0 facilitated the modeling of ET in Eu3+ complexes, and these features were validated through various studies published by our research group. LUMPAC 2.0 is based on a protocol proposed by de Sá and collaborators for the theoretical study of ET in Ln3+ compounds. However, alternative protocols have been proposed recently: Carneiro Neto and collaborators considered a greater number of ET channels; Georgieva and collaborators included the contribution of excited state geometry relaxation of the compound; and Beltrán-Leiva and collaborators employed fluorescence and phosphorescence calculations to interpret ligand to metal ET. Two Eu3+ complexes were studied using these methodologies with the support of LUMPAC 2.0 in a complementary manner. It was observed that the methodology proposed by Beltrán-Leiva and collaborators provided intraligand rates useful for the protocols by de Sá and collaborators and Carneiro Neto and collaborators to achieve better theoretical quantum yields, although improvements are still needed.