Computer simulation of an antiferroelectric liquid crystalline molecule: The origin of bent structure formation and the molecular packing property of MHPOBC in crystalline phase

Molecular orbital (MO) calculation and molecular dynamics (MD) simulation were carried out for an antiferroelectric liquid crystalline molecule, MHPOBC, to understand its conformational property and the origin of bent structure formation in crystalline phase. MO calculations performed for a chiral chain fragment of MHPOBC have determined the conformational state of each bond in the chiral chain. MD simulation, carried out for a system of 64 full MHPOBC molecules, has been able to reproduce the experimentally observed bent conformation and the molecular packing. The present study concludes that (1) the essential conformational feature of the chiral chain of MHPOBC is determined by intramolecular interactions, (2) MHPOBC can adopt two major conformations, i.e., linear and bent conformations, and (3) the bent conformation is selected in the crystalline phase as a consequence of intermolecular steric interactions.