Modelling the visible absorption spectra of copper(II) acetylacetonate by Density Functional Theory

Spin restricted open-shell Density Functional Theory calculations have been carried out by means of linear response theory to investigate the visible absorption spectrum of copper(II) acetylacetonate complex, Cu(acac)₂. The 3 d → 3 d transition energies and the influence of molecular structure and non-coordinating solvent on the spectra have been investigated. The obtained four 3 d → 3 d transition energies accord well with the experimental data in the crystal phase. The presented results indicate that the experimentally observed four band structure of Cu(acac)₂ is of molecular nature, and not caused by factor-group splitting in the crystal environment as previously suggested.