Our best value of the shift is -1.51 eV-it is computed from the spectrum based on 400 AIMD snapshots with 20 QM waters and using the IEs of 5 waters (AIMD/400, 5w/20QM scheme) treated with fc-CVS-EOM-CCSD, to which we add the triples and basis-set corrections. This protocol yields the absolute value of the bulk IE of 538.75 eV. Our results agree well with the best experimental values by who reported the bulk water IE of 538.21±0.07 eV and the shift of 1.61±0.09 eV. The spectra of the bulk species reports on the structure of the solvent around the solute and its dynamic fluctuations. In particular, the spectrum of water reflects the contributions from different hydrogen-bonding patterns. Computationally, it is possible to break down the total computed spectra into different contributions, similarly to the analysis in other theoretical studies 10,56 . Fig. shows the breakdown of the total spectrum into the contributions from structures with different hydrogen-bonding patterns. Panel (a) shows contributions from snapshots where the central water molecule forms a single donor-single acceptor (DA), single donor-double acceptor (DAA), double donor-single acceptor (DDA), and double donor-double acceptor (DDAA) hydrogen bonds. Collectively, these types of structures add up to 97.2% of the structures sampled in the simulation. The shape of the band is dominated by the DDAA pattern, which has the largest population. The structures in which the central water water acts as hydrogen-bond donor yield red-shifted IEs and the structures in which the central water acts as hydrogen-bond acceptor are blue shifted. The DDAA motif, in which there is an equal number of both kinds of hydrogen bonds, features a high-energy and a low-energy peaks. The DDA and DAA motifs have peaks at lower and higher energies, respectively.