THE IMPORTANCE OF COOPERATIVITY FOR THE PROPERTIES OF LIQUID WATER

The cooperativity of H-bonds is a fundamental property in liquid water and alcohols. H-bond energies are in liquid water about 250% stronger compared with H bonds of H2O monomers in solutions. Different spectro scopic techniques fundamental bands, overtone bands, so-called simulta neous bands of neighbouring H-bonded OH groups by one quantum, coopera tivity spectroscopy comparison between alcohol and water spectra, solu tion spectra and discussion of IR intensities could together give a un ique model of such liquids. The strong influence of cooperativity on p roperties of liquid water and alcohols dominates under saturation cond itions until about 230 degrees C, The anomalous water adsorption on su rfaces is one example of the importance of cooperativity on properties of water. The anomalous viscosity of water-alcohol mixtures demonstra tes the importance of non-H-bondd OH groups in liquid water. The IR ov ertone spectra show these groups but the fundamental is more difficult . We approximate the complex large clusters below 130 degrees C as des cribed by a simple equilibrium of cooperative H-bonded and non-bonded OH groups. Equilibrium constants and H-bond energies are estimated. Th e coupling with weak cooperative H-bonds near the cluster surfaces are discussed. (C) 1998 Elsevier Science B.V. All rights reserved.