Ground and excited states of zinc phthalocyanine studied by density functional methods

The first time-dependent DFT study of the excited states of ZnPc is presented. The theoretical results provide an accurate description of the UV-vis and vacuum-UV spectra and prove to be in excellent agreement with gas-phase spectra and generally in line with deconvolution analyses of solution and Ar/matrix absorption and MCD spectra. The nature and intensity of the main spectral features are highlighted and interpreted on the basis of the ground state electronic structure of the complex. A fragment approach where the four benzopyrrole rings and the aza bridges are taken as building blocks has proven to be a very important tool to fully understand the energy and composition of the MOs involved in the transitions and, from these, the excitation energies and intensities. The Gouterman a