Dielectric and thermal relaxation in the energy landscape

TL;DR

This paper introduces an energy landscape perspective to dielectric relaxation in undercooled liquids, explaining relaxation processes and their observed splitting, and demonstrating the equality of thermal and dielectric relaxation times with literature data.

Contribution

It presents a novel energy landscape interpretation of dielectric relaxation, linking structural rearrangements to relaxation stages and explaining the equality of thermal and dielectric relaxation times.

Findings

Energy landscape explains dielectric relaxation times.

Splitting of flow process into initial and final stages.

Thermal and dielectric relaxation times are equal, supported by literature data.

Abstract

We derive an energy landscape interpretation of dielectric relaxation times in undercooled liquids, comparing it to the traditional Debye and Gemant-DiMarzio-Bishop pictures. The interaction between different local structural rearrangements in the energy landscape explains qualitatively the recently observed splitting of the flow process into an initial and a final stage. The initial mechanical relaxation stage is attributed to hopping processes, the final thermal or structural relaxation stage to the decay of the local double-well potentials. The energy landscape concept provides an explanation for the equality of thermal and dielectric relaxation times. The equality itself is once more demonstrated on the basis of literature data for salol.