The Plastic and Liquid Phases of CCl$_3$Br Studied by Molecular Dynamics Simulations

TL;DR

This study uses molecular dynamics simulations to compare the liquid and plastic crystalline phases of CCl$_3$Br, revealing similar behaviors with differences at rare short-range molecular separations and distinct rotational dynamics across phases.

Contribution

It introduces a classification method to analyze short-range orientational order and characterizes the rotational dynamics in both phases.

Findings

Both phases exhibit similar short-range orientational order.

Rotational dynamics are isotropic in the liquid phase.

Transition to the plastic phase alters the rotational relaxation behavior.

Abstract

We present a molecular dynamics study of the liquid and plastic crystalline phases of CCl$_3$Br. We investigated the short-range orientational order using a recently developed classification method and we found that both phases behave in a very similar way. The only differences occur at very short molecular separations, which are shown to be very rare. The rotational dynamics was explored using time correlation functions of the molecular bonds. We found that the relaxation dynamics corresponds to an isotropic diffusive mode for the liquid phase, but departs from this behavior as the temperature is decreased and the system transitions into the plastic phase.