Measures of chirality in the framework of atom-atom potentials

Recently, different chirality measures were suggested to quantify the ability of chiral molecules to twist a nematic phase (twisting power). In this presentation, some of these measures are reviewed, and a few novel methods are suggested and considered. They are based on intermolecular interaction calculations within the framework of atom-atom potentials which are widely used in quantum chemistry, molecular dynamics calculations, etc. The novel chirality measures originate from calculating intermolecular interactions between a single chiral molecule and a small cluster of aligned non-chiral rods surrounding the chiral molecule. We consider different chiral “components” of intermolecular interactions (torques, forces, and energies) and discuss their applicability as chirality measures of the chiral molecule. The torque seems to be one of the most convenient chirality measures. Analytical calculations are made for the cases of atomic chirality and atropoisomers. The latter case correlates well with experimental data on helical pitch measurements.