Hydrogen bonds and dynamics of liquid water and alcohols

TL;DR

This paper investigates the molecular dynamics and phase transition mechanisms of water and alcohols, emphasizing hydrogen bonding, van der Waals interactions, and collective behaviors influencing their temperature-dependent properties.

Contribution

It introduces modified Arrhenius models to analyze activation energies and elucidates the role of hydrogen bonds and collective dynamics in water's anomalies and phase transitions.

Findings

Hydrogen bonds and van der Waals interactions regulate molecular motion.

Anomalies in water properties are linked to fluctuating dipoles and resonant excitation.

Collective dynamics of ice-like structures influence deviations from classical models.

Abstract

Using modified Arrhenius approximations, the activation energies of water, alcohols, and hexane structure rearrangement reactions responsible for temperature dependences of their dynamic and dielectric characteristics were determined. The interactions of van der Waals and charged centers of water and alcohol molecules regulate translational and rotational motion of molecules, ensuring coordination and balance of thermal effects of exothermic and endothermic reactions of changes in local structure of liquid. The long range action of fluctuating dipoles of hydrogen bonds and their resonant excitation by thermal energy underlies the anomalies in temperature dependences of water properties and initiates its phase transitions at points 273 K and 298 K. The deviation of the molecular dynamics of water from Arrhenius and Stokes Einstein equations in range from 273 to 298 K was associated with a high contribution of collective dynamics of ice like phase of water consisting of a network of hydrogen bonds structured by hexagonal clusters of Ih ice.