Calculation of stabilization energy of parallel hexane molecules

Molecular-mechanics method has been used for calculation od stable configurations of n-hexane pairs and triads in extended all-trans conformations with full translational and rotational freedom of the molecules during optimization. The calculated stabilization energies and equilibrium distances have been compared with the experimental data obtained for molecular crystals of paraffins. The comparison enables to distinguish the effects characteristical of the collective packing forces in the crystal. The optimum configurations of some hexane pairs have also been calculated by the quantum-chemical PCILO method. The results indicate superiority of MMC to the quantum-chemical methods and other empirical calculation procedures for the purposes of the stabilization energy determination.