(coupled cluster singles and approximate doubles) and CCSD (coupled cluster singles and doubles). In particular, we will investigate whether the shortcomings of the transition potential DFT (TP-DFT) methods in the description of the post-edge region of the nitrogen K-edge spectra of the solutes can be overcome. CC2 and CCSD calculations of the XA spectral parameters were performed using Dalton applying the core-valence separation during the solution of the coupled-cluster eigenvalue equations to selectively target the core-excited states. The polarizable-embedding (PE) The remaining water molecules (H and O atoms thereof) were used as reference points for the PE description of the molecular mechanics (MM) environment. A model of the chosen QM/MM space is shown in Figure . and with and without the PE environment. The results clearly show that including a PE description of the solvation environment is important. We then further analyzed the effect of different choices of the PE parameters. Among other aspects, we investigated the differences between using isotropic versus anisotropic polarizabilities in the PE, see Figure . Modest, yet noticeable, differences were observed, therefore anisotropic polarizabilities were subsequently used as considered more accurate. The importance of effective external field (EEF)