arrow
Volume 23, Issue 5
Numerical Study of the Isotropic-Nematic Phase Transition in Liquid Crystals Using the String Method

Yunzhi Li & Weiqing Ren

Commun. Comput. Phys., 23 (2018), pp. 1534-1548.

Published online: 2018-04

Export citation
  • Abstract

We consider a system of liquid crystal modeled by hard spherocylinders. In certain range of the pressure, the system exhibits two metastable phases: the isotropic phase and the nematic phase. In the isotropic phase, the spherocylinders are randomly packed. In contrast, the spherocylinders are well-ordered in the nematic phase. The isotropic-nematic phase transition is a rare event because it involves the crossing of energy barrier(s). This makes direct simulations, e.g. using molecular dynamics, of the transition event infeasible. In this paper, we study the phase transition in a coarse-grained space formed by two collective variables: the order parameter of the spherocylinders and the volume of the system. We compute the free energy in the collective variable space, the minimum free energy path (MFEP) between the isotropic phase and the nematic phase, and the transition state. Our results reveal the multilayer structure of the critical nucleus. The nucleus will grow further and evolve to the nematic phase after it crosses the energy barrier.

  • AMS Subject Headings

65Z05, 70E55, 82D25

  • Copyright

COPYRIGHT: © Global Science Press

  • Email address
  • BibTex
  • RIS
  • TXT
@Article{CiCP-23-1534, author = {}, title = {Numerical Study of the Isotropic-Nematic Phase Transition in Liquid Crystals Using the String Method}, journal = {Communications in Computational Physics}, year = {2018}, volume = {23}, number = {5}, pages = {1534--1548}, abstract = {

We consider a system of liquid crystal modeled by hard spherocylinders. In certain range of the pressure, the system exhibits two metastable phases: the isotropic phase and the nematic phase. In the isotropic phase, the spherocylinders are randomly packed. In contrast, the spherocylinders are well-ordered in the nematic phase. The isotropic-nematic phase transition is a rare event because it involves the crossing of energy barrier(s). This makes direct simulations, e.g. using molecular dynamics, of the transition event infeasible. In this paper, we study the phase transition in a coarse-grained space formed by two collective variables: the order parameter of the spherocylinders and the volume of the system. We compute the free energy in the collective variable space, the minimum free energy path (MFEP) between the isotropic phase and the nematic phase, and the transition state. Our results reveal the multilayer structure of the critical nucleus. The nucleus will grow further and evolve to the nematic phase after it crosses the energy barrier.

}, issn = {1991-7120}, doi = {https://doi.org/10.4208/cicp.OA-2017-0100}, url = {http://global-sci.org/intro/article_detail/cicp/11225.html} }
TY - JOUR T1 - Numerical Study of the Isotropic-Nematic Phase Transition in Liquid Crystals Using the String Method JO - Communications in Computational Physics VL - 5 SP - 1534 EP - 1548 PY - 2018 DA - 2018/04 SN - 23 DO - http://doi.org/10.4208/cicp.OA-2017-0100 UR - https://global-sci.org/intro/article_detail/cicp/11225.html KW - Phase transition, liquid crystal, order parameter, collective variables, string method AB -

We consider a system of liquid crystal modeled by hard spherocylinders. In certain range of the pressure, the system exhibits two metastable phases: the isotropic phase and the nematic phase. In the isotropic phase, the spherocylinders are randomly packed. In contrast, the spherocylinders are well-ordered in the nematic phase. The isotropic-nematic phase transition is a rare event because it involves the crossing of energy barrier(s). This makes direct simulations, e.g. using molecular dynamics, of the transition event infeasible. In this paper, we study the phase transition in a coarse-grained space formed by two collective variables: the order parameter of the spherocylinders and the volume of the system. We compute the free energy in the collective variable space, the minimum free energy path (MFEP) between the isotropic phase and the nematic phase, and the transition state. Our results reveal the multilayer structure of the critical nucleus. The nucleus will grow further and evolve to the nematic phase after it crosses the energy barrier.

Yunzhi Li & Weiqing Ren. (2020). Numerical Study of the Isotropic-Nematic Phase Transition in Liquid Crystals Using the String Method. Communications in Computational Physics. 23 (5). 1534-1548. doi:10.4208/cicp.OA-2017-0100
Copy to clipboard
The citation has been copied to your clipboard