Liquid crystals establish a nearly unique combination of thermodynamic, hydrodynamic, and topological behavior. This poses a challenge to their theoretical understanding and modeling. The arena where these effects come together is the mesoscopic (micron) scale. It is then important to develop models aimed at capturing this variety of dynamics. We have generalized the particle-based multiparticle collision dynamics (MPCD) method to model the dynamics of nematic liquid crystals. Following the Qian-Sheng theory [Phys. Rev. E 58, 7475 (1998)1063-651X10.1103/PhysRevE.58.7475] of nematics, the spatial and temporal variations of the nematic director field and order parameter are described by a tensor order parameter. The key idea is to assign tensorial degrees of freedom to each MPCD particle, whose mesoscopic average is the tensor order parameter. This nematic MPCD method includes backflow effect, velocity-orientation coupling, and thermal fluctuations. We validate the applicability of this method by testing (i) the nematic-isotropic phase transition, (ii) the flow alignment of the director in shear and Poiseuille flows, and (iii) the annihilation dynamics of a pair of line defects. We find excellent agreement with existing literature. We also investigate the flow field around a force dipole in a nematic liquid crystal, which represents the leading-order flow field around a force-free microswimmer. The anisotropy of the medium not only affects the magnitude of velocity field around the force dipole, but can also induce hydrodynamic torques depending on the orientation of dipole axis relative to director field. A force dipole experiences a hydrodynamic torque when the dipole axis is tilted with respect to the far-field director. The direction of hydrodynamic torque is such that the pusher- (or puller-) type force dipole tends to orient along (or perpendicular to) the director field. Our nematic MPCD method can have far-reaching implications not only in modeling of nematic flows, but also to study the motion of colloids and microswimmers immersed in an anisotropic medium.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1103/PhysRevE.99.063319 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Modeling and Elucidating the Behavior of a Thermoresponsive LCST Ionic Liquid.
J Chem Inf Model
January 2025
Donostia International Physics Center (DIPC), 20018 Donostia-San Sebastián, Spain.
Desalination of seawater by forward osmosis is a technology potentially able to address the global water scarcity problem. The major challenge limiting its widespread practical application is the design of a draw solute that can be separated from water by an energetically efficient process and then reused for the next cycle. Recent experiments demonstrate that a promising draw solute for forward-osmosis desalination is tetrabutylphosphonium 2,4,6-trimethylbenzenesulfonate ([P][TMBS]).
View Article and Find Full Text PDFPerformance Tuning of Polarizable Gaussian Multipole Model in Molecular Dynamics Simulations.
J Chem Theory Comput
January 2025
Chemical and Materials Physics Graduate Program, Departments of Molecular Biology and Biochemistry, Chemical and Biomolecular Engineering, Materials Science and Engineering, and Biomedical Engineering, University of California, Irvine, Irvine, California 92697, United States.
Molecular dynamics (MD) simulations are essential for understanding molecular phenomena at the atomic level, with their accuracy largely dependent on both the employed force field and sampling. Polarizable force fields, which incorporate atomic polarization effects, represent a significant advancement in simulation technology. The polarizable Gaussian multipole (pGM) model has been noted for its accurate reproduction of ab initio electrostatic interactions.
View Article and Find Full Text PDFSolvatochromic charge model of isonitrile probes for investigating hydrogen-bond dynamics with 2DIR spectroscopy.
J Chem Phys
January 2025
Department of Chemistry - Ångström Laboratory, Uppsala University, SE-75120 Uppsala, Sweden.
Isonitrile-derivatized amino acids are emerging as highly effective infrared (IR) probes for investigating the structures and dynamics of hydrogen (H)-bonds. These probes enable the quantification of chemical exchange processes in solute-solvent complexes via two-dimensional IR spectroscopy and hold significant promise for site-specific dynamic studies within proteins. Despite their potential, theoretical models that elucidate the solvatochromism of isonitriles remain underdeveloped.
View Article and Find Full Text PDFD3-ImgNet: A Framework for Molecular Properties Prediction Based on Data-Driven Electron Density Images.
J Phys Chem A
January 2025
Liaoning Key Laboratory of Manufacturing System and Logistics Optimization, Shenyang 110819, China.
Artificial intelligence technology has introduced a new research paradigm into the fields of quantum chemistry and materials science, leading to numerous studies that utilize machine learning methods to predict molecular properties. We contend that an exemplary deep learning model should not only achieve high-precision predictions of molecular properties but also incorporate guidance from physical mechanisms. Here, we propose a framework for predicting molecular properties based on data-driven electron density images, referred to as D3-ImgNet.
View Article and Find Full Text PDFUnderstanding the interaction mechanisms of active compounds extracted from Tabernaemontana penduliflora on the surface of magnetite (111) nanoparticles in aqueous medium by DFT and MD approaches.
J Mol Graph Model
March 2025
Center of Excellence African on future Energies and Systems Electrochemical (ACE-FUELS), University Federal Technology, PMB 1526, Owerri, State from Imo, Nigeria.
Computational techniques have been used to analyze the molecules of 10-hydroxycoronahydine (HC) and voacangine hydroxyindolenine (VH) molecules with the aim of studying the effect of base and temperature on their interaction mechanisms during synthesis green magnetite nanoparticles. Density functional theory (DFT) descriptors such as: energy gap, overall reactivity descriptors, dipole moment and adsorption energy have all been explored in depth to understand the nature of the interaction. The DFT results showed that the molecules studied (HC and VH) are interactive and stable in an aqueous medium, due to the fact that these molecules have free electronic doublets on the nitrogen atom and the bond of the aromatic ring.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!