Gay-Berne model

Kurst G R, R A Stephens and R W Phippen 1990. Computer Simulation Studies of Anisotropic iystems XIX. Mesophases Formed by the Gay-Berne Model Mesogen. Liquid Crystals 8 451-464. e F J, F Has and M Orozco 1990. Comparative Study of the Molecular Electrostatic Potential Ibtained from Different Wavefunctions - Reliability of the Semi-Empirical MNDO Wavefunction. oumal of Computational Chemistry 11 416-430. 

The implementation of this formalism for an atomistic model does not present any difficulties, at least conceptually. However, it is not obvious how the formalism should be used for single site potentials such as the Gay-Berne model. One approach would be to superimpose a mesogenic structure on the Gay-Berne ellipsoid but this structure would necessarily have a lower symmetry. Alternatively it would be possible to place a line of atoms along... 

A common feature of many mesogenic molecules is the presence of polar substituents and aromatic cores [3]. The electrostatic interactions between such groups can be incorporated into a molecular potential with the addition of dipolar and quadrupolar terms, respectively. Rather than represent these permanent electrostatic interactions by using a model in which a charge distribution is scattered over the surface of the molecule, it is very common to use one (or more) point multipoles [2,29]. Thus for an electrostatic Gay-Berne model, the pair potential is given by the sum... 

A similar model has been used to study the effect of a quadrupolar interaction on a system of Gay-Berne discs [27]. In this case, the bare Gay-Berne model... 

Figure 8. Phase diagram of the Gay-Berne model with the original and the most-studied parameterization (k = 3, k = 5, fi = 2, v = 1) in the density-temperature plane as obtained from computer simulations. Filled diamonds mark simulation results the phase boundaries away from these points are drawn as a guide only. The domains of the thermodynamic stability of the isotropic (/), nematic (N), and smectic (SB) phases are shown. The liquid-vapor critical point is denoted by C. Two-phase regions are shaded. (Reproduced from Ref. 104.)...

Fukunaga H, Takimoto J, Doi M. 2004. Molecular dynamics simulation study on the phase behavior of the Gay Berne model with a terminal dipole and a flexible tail. J Chem Phys 120(16) 7792 7800. 

GB) potential [284] considers, in addition, the orientation of the molecules with respect to their interdistance vector. Sometimes, the repulsive part is replaced by a hard core [189, 285], The Gay-Berne model forms nematic and SmA and SmB phases [189, 286] and, although far from being a realistic microscopic description of a nematic phase, currently represents the most appropriate model for the simulation of liquid crystalline states. 

Wilson M R 1997 Molecular dynamics simulations of flexible liquid crystal molecules using a Gay-Berne/Lennard-Jones model J. Chem. Phys. 107 8654-63... 

In simple single-site liquid crystal models, such as hard-ellipsoids or the Gay-Berne potential, a number of elegant techniques have been devised to calculate key bulk properties which are useful for display applications. These include elastic constants for nematic systems [87, 88]. However, these techniques are dependent on large systems and long runs, and (at the present time) limitations in computer time prevent the extension of these methods to fully atomistic models. 

Wilson MR (1996) GBMOL, a molecular dynamics package for modeling systems composed of Lennard-Jones and Gay-Berne particles... 

There have been several simulations of discotic liquid crystals based on hard ellipsoids [41], infinitely thin platelets [59, 60] and cut-spheres [40]. The Gay-Berne potential model was then used to simulate the behaviour of discotic systems by Emerson et al. [16] in order to introduce anisotropic attractive forces. In this model the scaled and shifted separation R (see Eq. 5) was given by... 

---