Fig. 5. (a) Gibbs free energies of adsorption (373 K) of ethanol monomer and dimer species with 1–6 co-adsorbed H₂O (n) calculated by AIMD, referenced to gas-phase ethanol molecules. Vertical dashed line indicates the locally stable pure-H₂O cluster size . (b) Gibbs free energy of adsorption (373 K) for ethanol monomer and dimer species at H₂O coverages corresponding to the local minima of (a) and compared to ethanol monomer and dimer adsorption in the gas phase. W_(intra) refers to intrapore water at other pure H₂O clusters and is calculated from the intensive Gibbs free energy of water within the Beta pore. (c) Representative geometries of the stable water cluster , ethanol monomer cluster , ethanol dimer cluster , and the ethanol–water dimer cluster formed by adsorption of one ethanol molecule at the stable monomer cluster .