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.