The LED breakdown of allows for a clear-cut quantification to all hydrogen-bonding interactions in these systems. These interactions are visualized in Fig. using the -fragmentpairwise LED interaction maps‖, where each element in the map corresponds to a specific interaction between two fragments in the molecular cluster and the entire interaction energyincluding the electronic preparationis distributed among the fragment pairs. The water molecules in the boat conformer are engaged in hydrogen bonds of similar strength, with interaction energies ranging from -7.1 to -7.6 kcal/mol. By contrast, the hydrogen bonding interaction energies in the prism conformer vary from -2.3 to -9.8 kcal/mol. The origin of this difference lies in the hydrogen bonding patterns of the two conformers. In the boat conformer, each water molecule donates one proton to another water molecule while simultaneously accepting one proton from a different water molecule. In contrast, the prism conformer features water molecules that accept or donate varying numbers of hydrogen bonds. Generally, the strongest interactions occur when a water molecule with both lone pairs involved in hydrogen bonds donates one of its protons to a water molecule with both protons engaged in hydrogen bonds, as seen in the W 2 -W 3 and W 5 -W 6 interactions in the prism conformer. This effect is inherently cooperative, arising from the charge redistribution: the hydrogen bond donor atom becomes more negatively charged upon the formation of a hydrogen bond, while the acceptor atom becomes more positively charged. Indeed, decomposition of into fragment-pairwise terms quantifies these chemically intuitive findings, showing larger values precisely for the W 2 -W 3 and W 5 -W 6 interactions in the prism conformer.