Identification of structural relaxation in the dielectric response of water

TL;DR

This paper investigates the dielectric response of water, revealing that its structural relaxation manifests as a high-frequency shoulder, while the main peak is linked to supramolecular structures, challenging traditional interpretations.

Contribution

It clarifies the nature of dielectric relaxation in water, distinguishing between structural relaxation and supramolecular contributions, which was previously ambiguous.

Findings

Structural relaxation appears as a high-frequency shoulder in water's dielectric spectra.

The main dielectric peak is associated with supramolecular structures.

Results differentiate water's dielectric behavior from mono-alcohols.

Abstract

One century ago pioneering dielectric results obtained for water and n-alcohols triggered the advent of molecular rotation diffusion theory considered by Debye to describe the primary dielectric absorption in these liquids. Comparing dielectric, viscoelastic, and light scattering results we unambiguously demonstrate that the structural relaxation appears only as a high-frequency shoulder in the dielectric spectra of water. In contrast, the main dielectric peak is related to a supramolecular structure, analogous to the Debye-like peak observed in mono-alcohols.