Synergism of dynamics of tetrahedral hydrogen bonds of liquid water

Abstract

We used modified Arrhenius approximations to analyze known temperature dependences (TDs) of water microstructure parameters and its dielectric and dynamic characteristics. Analysis of activation energies showed a significant difference in the molecular dynamics of water in ranges 273–298 and 300–373 K. Features of TDs in the first range were associated with the dynamics of a metastable ice-like phase of water, in which hexagonal clusters with tetrahedral hydrogen bonds (HBs) predominate. Based on ratios of signs and values of activation energies of HBs' fluctuations and parameters of a microstructure, it was assumed that fluctuations of HBs' dipoles play a key role in the mechanism of resonant activation by a thermal energy of concertedly reactions of deformation, rupture, and formation of tetrahedral HBs in water clusters. Synergism of these reactions and interaction of charges of the vacant acceptor and donor tetrahedral orbitals of an oxygen atom trigger at 298 K an explosive transition of a metastable ice-like phase of water into an argon-like phase. Synergy of water dynamics above 298 K is adequately characterized by the product Dη, from which TDs follow the activation energies of reactions that determine the form of Stokes–Einstein relation in temperature ranges below and above 298 K point.