A DFT/TDDFT study of Li+ and Mg2+ interactions with ketocyanine dye

Density Functional Theory calculations have been used to study the complexation of a ketocyanine dye with Li+ and Mg2+ ions. Structures of dye-ion complexes and singlet transition energies have been found in vacuum and in the acetonitrile solution using different DFT functionals. It has been demonstrated that accounting for the solvent effect plays crucial role in correct reproduction of electronic spectrum of complexed dye. The best agreement between calculated transition energies or spectral red shifts and experimental values has been obtained for hybrid O3LYP functional.