Molecular kinetics of solid and liquid CHCl$_3$

TL;DR

This study investigates the molecular rotational dynamics of CHCl₃ across solid and liquid phases using nuclear quadrupolar resonance and molecular dynamics simulations, revealing isotropic rotations in supercooled liquids.

Contribution

It combines experimental and simulation methods to analyze molecular kinetics and local structure of CHCl₃ during phase transition.

Findings

Molecular rotations about the C-H bond occur in the pre-melting solid.

Rotations become isotropic in the liquid phase, even under supercooled conditions.

Nuclear quadrupolar resonance and molecular dynamics provide complementary insights.

Abstract

We present a detailed analysis of the molecular kinetics of CHCl$_3$ in a range of temperatures covering the solid and liquid phases. Using nuclear quadrupolar resonance we determine the relaxation times for the molecular rotations in solid at pre-melting conditions. Molecular dynamics simulations are used to characterize the rotational dynamics in the solid and liquid phases and to study the local structure of the liquid in terms of the molecular relative orientations. We find that in the pre-melting regime the molecules rotate about the C-H bond, but the rotations are isotropic in the liquid, even at supercooled conditions.