Activation energy of water structural transitions

•Temperature dependencies of water properties have different activation energies.•Break of hydrogen bonds limits diffusion and electric relaxation in water.•Rotation of water clusters limits the thermodynamics of its static properties.

In this work, the nature of molecular motions that dominate in the thermodynamics of anomalies of liquid water properties in the range of 0–100 °С has been studied. Temperature dependencies of water properties have been approximated by exponential functions and the activation energies for water structure transitions have been evaluated. The activation energy values were compared with the energy spectra of characteristic vibrations and with those of cooperative molecular motion in the lattice-type structure of hydrogen bonds. It has been found that it is the reaction of hydrogen bond breaking that mainly limits the abnormal dynamics of water viscosity, self-diffusion, dielectric relaxation time and electric conductivity. It has been assumed that the thermodynamics of cooperative motion and resonance phenomena in water clusters form a basis for the differentiation mechanism of extrema points in temperature dependencies of water density, isobaric heat capacity, sound velocity, surface tension coefficient and compressibility.

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