The chiral dipolar hard sphere model

Abstract

A simple molecular model of chiral molecules is presented in this paper: the chiral dipolar hard sphere model. The discriminatory interaction between enantiomers is represented by electrostatic (or magnetic) dipole–dipole interactions: short ranged steric repulsion are represented by hard sphere potential and, in each molecule, two point dipoles are located inside the sphere. The model is described in detail and some of its elementary properties are given; in particular, it is shown that the knowledge of only three multipole spherical components (namely: , and ) allows one to compute all multipole spherical components of the model. Despite, the simplicity of the model, it is shown also that the energy landscape of the interaction between two enantiomers is quite rich, this renders systems of chiral dipolar hard sphere very interesting and complicated to study. Few preliminary Monte Carlo simulation results are also reported in the paper. Last, but not least, this paper is dedicated to Jean-Jacques Weis.

Keywords:

• chirality
• Monte Carlo simulations
• liquid crystals

Acknowledgements

The author acknowledges computation facilities provided by the Institut du Développement et des Ressources en Informatique Scientifique (IDRIS) under projects 0682104 and 0992104.

In the middle of the 1990s Jean-Jacques was my PhD supervisor; I have to say that I have been very lucky to benefit of his broad knowledge in the physics of liquids and in computer simulations. Therefore, I am extremely glad to dedicate this paper to Jean-Jacques Weis in this special issue of Molecular Physics in his honour.

Notes

Notes

1. D.P. Craig and D.P. Mellor 3 have chosen the term chirodiastaltic (‘diastaltic’ ≡ ‘serving to distinguish’) because of its explicit reference to chirality. Another terminology diastereotopic has been introduced by Bosnich et al. 32.

2. An example of an achiral model of dipolar hard spheres possessing two colinear dipoles is given in 46.