An accurate quantum chemical description of water systems can only be achieved for small water clusters. These limitations demand that we approximate our molecular systems with small models. Despite their reduced size, model systems can often produce insightful information for a variety of chemical problems. For our study, we wanted to understand the behaviour of binding energies between organic molecules and water clusters of increasing size. For this purpose, we retrieved the water clusters produced by Temelso and coworkers that range in size from the monomer to the decamer. A summary of the structures studied in this paper is shown in Table , and an example of them is displayed in Figure . Temelso et al. obtained these structures at the RI-MP2 /aug-cc-pVDZ 34 level of theory, making them appropriate for benchmarking purposes. We also selected the following seven organic molecules as representative of species that are present in AOC reactions: acetone, dimethyl ether, oxirane, methyl acetate, azomethane, dimethylamine, and trimethylamine, which we pre-optimized at B3LYP /6-31+G** using Gaussian 16 (g16). This selection was based on their similarity to organic substrates involved in "on water" reactions. We used these organic molecules as probes to study the HB donating capabilities of -OH groups in small water clusters. For the sake of simplicity, we will often refer to these organic molecules as probes in this work. The complexes formed by the interactions between the probes and water clusters of various sizes could take on any one of a large number of configurations: as water cluster sizes increase, so does the number of available -OH donor groups with which the acceptors can interact. To explore different complexes, we fixed the coordinates of the water clusters and allowed the pre-optimized probes to freely move around the water clusters using a random generator of coordinates to obtain 2000 structures per water cluster-probe complex, followed by an approach with intermediate computational expense steps to refine the data set. The module genmer from the Molclus software was employed to generate the 2000 configurations for each complex. Next, we performed single-point (SP) calculations on these geometries and energy-ranked them using the UFF force-field, and eliminated the 1000 least stable complexes (step I). In step II, we computed the single-point energy of the remaining 1000 compounds using HF-D3(BJ)/MINIs-ACP and reordering the structures based on electronic energy. The 500 least stable structures were removed from the list.