Using the outlined configurational sampling protocol we studied the (PA) 1 (w) 0-5 , (LA) 1 (w) 0-5 , (ProA) 1 (w) 0-5 , and (diol) 1 (w) 0-5 cluster systems. Figure presents the hydrated cluster geometries of PA (Figure ), LA (Figure ), ProA (Figure ), and the diol ( In no cases do we observe a proton transfer from the organic acids to water. As seen in Figure , the Tc conformer of PA was identified as the lowest free energy conformer, as expected. However, when hydrating the monomer, it takes the form of the Tt conformer within the (PA) 1 (w) 1-3 and (PA) 1 (w) 5 clusters. This can be ascribed to the PA monomer engaging in favorable hydrogen-bonding interactions with the surrounding water molecules thus impeding intramolecular hydrogen bonding between the carboxylic O-H donor and the α-carbonyl acceptor. In the (PA) 1 (w) 4 cluster, the Ct conformer of PA is observed instead but the configuration of the carboxylic acid moiety is retained as the Ct conformer is simply generated by a 180-degree rotation around the C-C bond of the two carbonyl groups of the Tc conformer. Generally, the water molecules are observed to reside at the carboxylic acid terminus of the PA monomer and the hydrogen bonding capacity of the carboxylic oxygens are observed to be saturated at the (PA) 1 (w) 4 cluster, i.e., the fifth water molecule in the (PA) 1 (w) 5 cluster engages in hydrogen bonding with the α-carbonyl group instead, thus serving as a water bridge to the adjacent four-water ensemble.