Freezing Transitions in the fluid of long elongated molecules

TL;DR

This paper uses density-functional theory and Percus-Yevick integral equations to analyze phase transitions in long elongated molecules, revealing direct freezing into smectic A and the stabilization of nematic phases at high temperatures and densities.

Contribution

It provides a theoretical analysis of phase transitions in elongated molecules, aligning with simulation results, and details the conditions for different phase stabilizations.

Findings

Fluid freezes directly into smectic A phase at low temperatures.

Nematic phase stabilizes between isotropic and smectic A at high temperatures and densities.

Results agree with computer simulation data.

Abstract

We have used the density-functional theory to locate the freezing transitions and calculate the values of freezing parameters for a system of long elongated molecules which interact via the Gay-Berne pair potential. The pair correlation functions of isotropic phase which enter in the theory as input informations are found from the Percus-Yevick integral equation theory. At low temperatures the fluid freezes directly into the smectic A phase on increasing the density. The nematic phase is found to stabilize in between the isotropic and smectic A phases only at high temperatures and high densities. These features of the phase diagram are in good agreement with the computer simulation results.