Wall-induced orientational order in athermal semidilute solutions of semiflexible polymers: Monte Carlo simulations of a lattice model

2013 ◽  
Vol 138 (23) ◽  
pp. 234903 ◽  
Author(s):  
V. A. Ivanov ◽  
A. S. Rodionova ◽  
J. A. Martemyanova ◽  
M. R. Stukan ◽  
M. Müller ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Simulations ◽  
Lattice Model ◽  
Orientational Order ◽  
Semiflexible Polymers ◽  
Semidilute Solutions

Computer simulation studies of anisotropic systems IV. The effect of translational freedom

1980 ◽  
Vol 373 (1752) ◽  
pp. 111-130 ◽  
Keyword(s):  
Monte Carlo ◽  
Lattice Model ◽  
Short Range ◽  
Orientational Order ◽  
Pair Potential ◽  
Field Approximation ◽  
Isotropic Phase ◽  
Spatial Order ◽  
Cylindrically Symmetric ◽  
Angular Correlation Function

We have simulated the properties of 256 cylindrically symmetric particles interacting via a simple anisotropic potential of the form u 2 (r 12 ) P 2 (cos B 12 ) and with a scalar Lennard-Jones 12:6 potential, using the Monte Carlo technique. The simulations were performed for two forms of u2(r12) in the isothermal-isobaric ensemble and yielded values for volume, enthalpy, second-rank orientational order parameter, radial distribution function and second-rank angular correlation function. The specific heat at constant pressure, isothermal compressibility and isobaric expansivity were also obtained but they are subject to considerable error because they were evaluated from fluctuations. The system is found to exhibit a weak, firstorder transition from a nematic to an isotropic phase on increasing the temperature. The isotropic phase possesses short-range spatial and orientational order; it differs from the nematic phase, which has longrange orientational order but only short-range spatial order. The results of these simulations are used to discuss the influence of the range of the anisotropic potential on the behaviour of the nematogen. Previous Monte Carlo simulations of nematic liquid crystals had employed a lattice model with the anisotropic interactions restricted to nearest neighbours. Our results are used to study the effect of these convenient but unrealistic restrictions on the properties of the nematic. The results of our simulations are in reasonable accord with the properties of the nematogen, 4,4'- dimethoxyazoxybenzene, although no attem pt was made to select a pair potential to mimic the behaviour of any substance. Finally, we use the results of our simulations to test the validity of the molecular field approximation, as applied to nematics. This approximation is one of the foundations of the Maier-Saupe theory and its predictions are compared with the behaviour of the simulated nematics. It would appear that this theory provides a better description of our system than the lattice model, with its enforced spatial order and truncated anisotropic pair potential.

scholarly journals Doping liquid crystals with nanoparticles. A computer simulation of the effects of nanoparticle shape

2016 ◽  
Vol 18 (4) ◽  
pp. 2428-2441 ◽  
Author(s):  
Silvia Orlandi ◽  
Erika Benini ◽  
Isabella Miglioli ◽  
Dean R. Evans ◽  
Victor Reshetnyak ◽  
...  
Keyword(s):  
Computer Simulation ◽  
Monte Carlo ◽  
Liquid Crystal ◽  
Liquid Crystals ◽  
Monte Carlo Simulations ◽  
Orientational Order ◽  
Nanoparticle Shape ◽  
Nanoparticle Dispersions ◽  
Molecular Scale ◽  
Clearing Temperature

Molecular-scale Monte Carlo simulations of liquid crystal-nanoparticle dispersions show the effect on the orientational order and on the clearing temperature of shape and concentration of the dopant nanoparticles.

scholarly journals Analysis of polytype stability in PVT grown silicon carbide single crystal using competitive lattice model Monte Carlo simulations

AIP Advances ◽  
2014 ◽  
Vol 4 (9) ◽  
pp. 097106 ◽  
Author(s):  
Hui-Jun Guo ◽  
Wei Huang ◽  
Xi Liu ◽  
Pan Gao ◽  
Shi-Yi Zhuo ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
Monte Carlo ◽  
Monte Carlo Simulations ◽  
Single Crystal ◽  
Lattice Model

THE ORIENTATIONAL AND STRUCTURAL PROPERTIES OF N2 and N2–AR SOLIDS AT HIGH PRESSURE

1999 ◽  
Vol 10 (02n03) ◽  
pp. 445-453 ◽  
Author(s):  
E. P. VAN KLAVEREN ◽  
J. P. J. MICHELS ◽  
J. A. SCHOUTEN
Keyword(s):  
High Pressure ◽  
Monte Carlo ◽  
Monte Carlo Simulations ◽  
Structural Changes ◽  
Orientational Order ◽  
Large Degree ◽  
Intermolecular Contact ◽  
Complicated Structure ◽  
Tetragonal Modification ◽  
Ε Phase

The high pressure phases of N 2 and N 2–Ar mixed solids at 7 GPa have been investigated using Monte Carlo simulations. Orientational order parameters and displacements of the molecules with respect to the positions of the space group were calculated. These tools provide an appropriate way to study these solids. In the ε* phase, the displacement Δ of the e sites was found to be 0.05 Å. In the [Formula: see text] phase, the orientational confinement to a disk of the N 2 molecules at the c sites increases with Ar concentration. Within this disk, the distribution is nonuniform, even at high temperatures. The orientationally ordered disk molecules show a displacement along the line of closest intermolecular contact. For the tetragonal modification of the [Formula: see text] phase, the c axis is perpendicular to these ordered and displaced disks. At high Ar concentrations, the [Formula: see text] phase shows a large degree of alignment of the disk molecules. In this phase, the equilibrium positions show a complicated structure. Therefore, there are small but significant structural changes between the [Formula: see text], [Formula: see text] and [Formula: see text] phases.

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