Having chosen the parametrization of the polarizable embedding, we then carried out XA spectral calculations at the CC2 and CCSD levels of theory for two randomly selected snapshot structures. The spectra are shown in Figure . Already based on these two structures, we noticed quite significant differences between the CC2 and the CCSD predictions, especially for the protonated species, which we considered a preliminary indication that the CC2 method might not be sufficiently accurate. Nonetheless, we opted to carry out the CC2 calculations on the complete set of available snapshots. Figure presents the final averaged XA spectra of the two methods. From this analysis, and having the experimental spectra in mind, we find that CC2 clearly fails in describing the nitrogen K-edge XA spectra of aqueous ammonia and ammonium, not only in post-edge, but even in the pre-edge region.