The computational evidence for the crucial role of the dipole cross-correlations in the polar glass-forming liquids

TL;DR

This study uses molecular dynamics simulations to demonstrate that dipole cross-correlations are crucial in strongly polar glass-forming liquids, significantly influencing their dielectric spectra, unlike in weakly polar liquids.

Contribution

It provides computational evidence highlighting the importance of dipole cross-correlations in the dielectric behavior of polar glass-forming liquids, supporting recent theoretical interpretations.

Findings

Cross-correlations are negligible in weakly polar liquids.

Cross-correlations dominate in strongly polar liquids.

Results support the interpretation of dielectric spectra in glass-forming liquids.

Abstract

In this letter, we analyze the dipole-dipole correlations obtained from the molecular dynamics simulations for strongly- and weakly-polar model liquids. As a result, we found that cross-correlations contribution to the systems total dipole moment correlation function, which is directly measured in the dielectric spectroscopy experiment, is negligible for weakly-polar liquids. In contrast, the cross-correlations term dominates over the self-correlations one for examined strongly polar-liquid. Consequently, our studies strongly support the interpretation of the dielectric spectra nature of the glass forming liquids, recently proposed by Pabst et al.