Nuclear magnetic resonance measurements reveal the origin of the Debye process in monohydroxy alcohols

TL;DR

This study uses nuclear magnetic resonance to investigate the Debye process in monohydroxy alcohols, revealing that transient chain structures are responsible for the observed dielectric relaxation phenomena.

Contribution

It introduces a self-restructuring chain model based on NMR and diffusion data to explain the Debye process in hydrogen-bonded glass formers.

Findings

Identification of intermediate, slower dynamics in n-butanol

Proposal of a self-restructuring chain model

Consistent explanation of dielectric and relaxation observations

Abstract

Monohydroxy alcohols show a structural relaxation and at longer time scales a Debye-type dielectric peak. From spin-lattice relaxation experiments using different nuclear probes an intermediate, slower-than-structural dynamics is identified for n-butanol. Based on these findings and on diffusion measurements, a model of self-restructuring, transient chains is proposed. The model is demonstrated to explain consistently the so far puzzling observations made for this class of hydrogen-bonded glass forming liquids.