Especially, the first transition peak at around 2.3 eV is described poorly. In the case of B-LYP, the first peak appears to align, however, at the expense of a worse description of the transitions beyond 3 eV or, as other studies have shown, at the expense of the wrong ordering of excited states. In general, the calculated transitions beyond 3 eV are inaccurate for all functionals. Unfortunately, there appears to be no systematic approach to improve the results by modifying the used functional, as each yields different transition energies and oscillator strengths. Next single-shot GW calculations were performed using the spectral method. From Fig. we observe that the results still depend as expected heavily on the starting point aka. the underlying DFT calculation. It appears that for certain functionals the quality of the obtained results worsens, as the lowest energy peak is strongly downshifted. This is the case for all functionals, however, to a lesser extent for the range-separated functional LC-BLYP. This is an important result, as it is known that single-shot GW energies align well with experimental values if functionals with large exact HF exchanges are used. Apparently, this also applies to systems with first-row transition metal complexes, where a single GW iteration is sufficient, to produce results that align roughly with experimental spectra.